DIVIDEND POLICY

        We intend to pay regular quarterly dividends to our stockholders beginning in the                quarter of 2010. The annual dividend target will be approximately 20% to 30% of the prior year's net income adjusted for unusual items. The decision to pay a dividend, however, remains within the discretion of our board of directors and may be affected by various factors, including our earnings, financial condition, capital requirements, level of indebtedness and other considerations our board of directors deems relevant. Future credit facilities, other future debt obligations and statutory provisions, may limit, or in some cases, prohibit, our ability to pay dividends.

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        The CBOE board of directors recommends that you vote "FOR" the adoption of the Agreement and Plan of Merger to accomplish the restructuring transaction and for any proposal that may be made by the Vice Chairman of the Board of the CBOE to adjourn or postpone the CBOE special meeting for the purpose of soliciting proxies.

Who Can Vote at the CBOE Special Meeting

        Each Voting Member of the CBOE of record and in good standing as of the close of business on                        , 2010, the record date for the meeting, will be entitled to vote on the matters presented at the meeting and at any adjournment thereof. On each proposal set forth at the CBOE special meeting, each Voting Member of the CBOE is entitled to one vote with respect to each membership for which the Voting Member of the CBOE has the right to vote. As of the record date, there are       total memberships entitled to vote. The CBOE currently holds one inactive "treasury" membership. This membership will not be voted and will not be converted into the demutualization consideration. This membership is not included in the number of memberships referenced above.

Vote Required

        The proposal to adopt the Agreement and Plan of Merger requires the affirmative vote of a majority of the outstanding CBOE memberships entitled to vote. As a result, if a CBOE member entitled to vote does not vote or abstains from voting on this proposal, it will have the same effect as a vote against the proposal .

        The presence in person or by proxy of CBOE members holding a majority of the total outstanding CBOE memberships entitled to vote shall constitute a quorum at the meeting.

        Directors and officers of the CBOE hold memberships entitling them to cast an aggregate of 14 votes on the proposal, representing approximately 1.4% of the total membership votes that may be cast.

Adjournments

        If no quorum of the CBOE members is present at the CBOE special meeting, the CBOE special meeting may be adjourned by the majority of the members present or represented by proxy and entitled to vote at that meeting from time to time, without notice other than announcement at the meeting, unless otherwise required by statute. If the Vice Chairman of the CBOE board of directors proposes to adjourn the CBOE special meeting and this proposal is approved by the CBOE members entitled to vote, the CBOE special meeting will be adjourned. At any adjourned meeting of the special meeting at which a quorum is present, any business may be transacted which might have been

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transacted at the special meeting as originally notified . In order for the special meeting to be adjourned, the proposal to adjourn the meeting must be approved by the majority of the members present or represented by proxy at the meeting and entitled to vote.

Manner of Voting

        If you are a Voting Member of the CBOE, you may cast your vote for or against the proposals submitted at the CBOE special meeting either in person at the meeting or by proxy prior to the time the meeting is called. To vote in person, you must be present at the special meeting and cast your ballot.

        The Election Committee (or their designees) will collect proxies in-person on the trading floor beginning            ,             , 2010. Two voting stations will be set up on the trading floor—near the escalators on the North and South walls (or at such other location as the Election Committee may designate).

        To vote by proxy, and avoid the inconvenience of in-person voting at the special meeting, you may submit your proxy at any time prior to the time the special meeting is called to order. The following materials are enclosed with this proxy statement and prospectus: a proxy card and a postage paid return envelope. These materials are also being delivered to Voting Members by email. You may submit your proxy card by mail in the postage paid envelope, by fax, by hand delivery to the Office of the Secretary on the 7th floor of the Exchange or to the voting stations on the trading floor, or you can submit your proxy through the internet or by telephone. When voting by proxy, your proxy card indicates how you wish to vote on the proposals at issue, and the proxy authorizes a designated person to cast your vote at the meeting and to vote on your behalf on any other matters that may properly come before the meeting.

        If you own or hold multiple memberships you will receive a single Control Number that will allow you to vote all of your memberships at once, except that Temporary Members will receive a separate Control Number for each Temporary Membership held.

        The following is a detailed description of how to vote by proxy using the telephone, internet and mail methods:

By Telephone (Available only until 3:30 p.m. Central Standard Time on            , 2010.)

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On a touch tone telephone, call TOLL FREE 1-888-693-8683, 24 hours a day, 7 days a week.



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You will be asked to enter ONLY the CONTROL NUMBER shown on the proxy card.



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Have your proxy card ready, and then follow the simple instructions.



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Your vote will be confirmed and cast as you directed.

**If you are voting by telephone, please do not mail your proxy card.

By Internet (Available only until 3:30 p.m. Central Standard Time on            , 2010.)

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Visit the internet voting Website at http://www.cesvote.com.



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Enter the CONTROL NUMBER shown on the proxy card and follow the instructions on your screen.



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You will incur only your usual internet charges.

**If you are voting by internet, please do not mail your proxy card.

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By Mail or Fax

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Mark the proxy card. LEGIBLY PRINT the voting member name (Individual Member or Member Organization), acronym (if applicable), and the name of the authorized signatory (e.g., executive officer) voting for a member organization (if applicable), on the proxy card. Be sure to indicate the legal name in which your membership is held.



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Sign and date your proxy card and either return your proxy card in the postage-paid envelope by            , 2010 or fax your proxy card to Corporate Election Services at 412-299-9191 by 3:30 p.m. Central Standard Time on                  , 2010.

**If you are voting by telephone or the internet, please do not mail your proxy card.

         You are encouraged to submit your proxy promptly in order to ensure timely receipt and an efficient election. You may verify receipt of your proxy at the voting stations on the trading floor or by contacting                        at                         or Jaime Galvan at (312) 786-7058 (galvanj@cboe.com).

        Upon completion of the vote count, the vote results will be posted on the Member's website at www.CBOE.com and on the Election Results Hotline at (312) 786-8150.

        Duly executed proxies authorizing the persons designated therein to cast your vote at the special meeting, must be received prior to     p.m., Central Time, on             , 2010 in order to be counted.

        All proxies (including those given by phone or through the internet) received before the deadline stated above or by any later established deadline for any adjourned meeting, as the case may be, will, unless revoked, be cast as indicated in those proxies. If no voting instruction is indicated on a proxy card, the CBOE membership(s) represented by the proxy card will be voted in accordance with the recommendation of the CBOE board of directors and, therefore, "FOR" the adoption of the Agreement and Plan of Merger to affect the restructuring transaction and "FOR" any proposal that may be made to adjourn or postpone the special meeting.

        If you return a properly executed proxy card and have indicated that you have abstained from voting on a proposal, your CBOE memberships represented by the proxy will be considered present at the CBOE special meeting for purposes of determining a quorum. We urge you to mark each applicable box on the proxy card or voting instruction card to indicate how to vote your CBOE membership.

        You may revoke your proxy at any time before it is cast by:

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submitting a written revocation dated after the date of the proxy that is being revoked to Chicago Board Options Exchange, Incorporated, Office of the Secretary, at 400 South LaSalle Street, Chicago, Illinois 60605;



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submitting a later-dated proxy by mail, fax, telephone or internet; or



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attending the CBOE special meeting and voting by paper ballot in person.

        Attendance at the CBOE special meeting will not, in and of itself, constitute revocation of a previously delivered proxy. If the CBOE special meeting is adjourned or postponed, it will not affect the ability of CBOE members to exercise their voting rights or to revoke any previously granted proxy using the methods described above.

        Returning your completed proxy will not prevent you from changing your vote or revoking your proxy and voting in person at the special meeting of voting members. Please note, however, that if you submit your proxy through one of the available methods, you will not need to attend the special meeting of members or take any further action in connection with the special meeting because you already will have directed your proxy to vote on your behalf with respect to the proposal to be brought at the special meeting.

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Confidential Voting

        It is the CBOE's policy that all proxies and voting tabulations that identify the CBOE members be kept confidential. The CBOE has engaged a third-party firm to serve as inspector of election and count the ballots. The CBOE Election Committee will oversee the third-party firm selected to count the ballots.

Solicitation of Proxies

        The CBOE board of directors is making this solicitation of proxies. The CBOE will pay the expenses incurred in connection with the printing and mailing of this document. Solicitation of proxies by mail may be supplemented by telephone and other electronic means, advertisements and personal solicitation by the directors, officers or employees of the CBOE. No additional compensation will be paid to our directors, officers or employees for soliciting proxies.

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THE RESTRUCTURING TRANSACTION

         This section of the document describes material aspects of the proposed restructuring transaction. This summary may not contain all of the information that is important to you. You should carefully read this entire document, including the full text of the Agreement and Plan of Merger, which is attached as Annex G, and the other documents we refer you to for a more complete understanding of the restructuring transaction. In addition, we incorporate important business and financial data about us into this document by reference. You may obtain the information incorporated by reference into this document without charge by following the instructions described under "Where You Can Find More Information," which begins on page 199.

General

        The restructuring transaction will be completed through the following steps:

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The creation of CBOE Holdings, Inc. as a new Delaware stock, for-profit subsidiary corporation, which occured on August 15, 2006, and CBOE Merger Sub, Inc. as a new second-tier, Delaware stock, for-profit corporation and wholly-owned subsidiary of CBOE Holdings, which occured on August 15, 2006.



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Pursuant to the Agreement and Plan of Merger to be entered into in the near future, CBOE Merger Sub, Inc. will merge with and into the CBOE, with the CBOE surviving the merger as a Delaware stock, for-profit corporation. We refer to this transaction as the "Merger."



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Upon the effectiveness of the Merger, the outstanding stock of CBOE Merger Sub, Inc. will be converted into common stock of the CBOE, the CBOE Seats existing on the date of the restructuring transaction will be converted into CBOE Holdings Class A common stock and the outstanding CBOE Holdings common stock already held by the CBOE will be cancelled for no consideration and shall cease to exist. As a result, CBOE Holdings will become the sole stockholder of the CBOE and will be entitled to the exclusive right to receive all dividends and distributions, including proceeds upon liquidation, from the CBOE and all associated voting rights.

        Immediately following the Merger, the CBOE will transfer to CBOE Holdings all of the shares or interests the CBOE owns in its subsidiaries (CBOE Futures Exchange, LLC, Chicago Options Exchange Building Corporation, CBOE, LLC, DerivaTech Corporation, Market Data Express, LLC, The Options Exchange, Incorporated, CBOE Execution Services, LLC and C2 Options Exchange, Incorporated), making them first-tier, wholly-owned subsidiaries of CBOE Holdings. CBOE Stock Exchange, LLC will remain a facility of the CBOE in which the CBOE holds a 49.96% interest.

        As part of the restructuring transaction, each CBOE Seat existing as of the date of the restructuring transaction will be converted into 80,000 shares of CBOE Holdings Class A common stock. In addition, as required by the Settlement Agreement, Participating Group A Settlement Class Members will be issued, immediately following the effectiveness of the Merger effecting the restructuring transaction, 18,774 shares of Class B common stock of CBOE Holdings for each Group A package held by such class member and approved by the Delaware Court.

        The restructuring transaction is contingent on the concurrent completion by CBOE Holdings of an underwritten initial public offering of its unrestricted common stock. CBOE Holdings currently expects to offer approximately            shares of its unrestricted common stock following the requisite approval of the restructuring transaction. In addition, CBOE Holdings intends to provide all holders of the Class A and Class B common stock with the opportunity to sell in the initial public offering a small portion of the shares of Class A and Class B shares to be received in the restructuring transaction and pursuant to the Settlement Agreement. The shares of Class A and Class B common stock to be sold by these selling stockholders will be converted into shares of our unrestricted common stock prior to being sold in the initial public offering. The actual number of shares to be offered and sold and the price at which such shares will be offered and sold in the initial public offering may be different than the

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assumptions provided in this proxy statement and prospectus, and the final decision about offering parameters will be determined by the CBOE Holdings board of directors.

         We may proceed with the restructuring transaction and the initial public offering without seeking additional member approval only if CBOE Holdings can complete the initial public offering at a price per share of at least $            and by CBOE Holdings selling at least                  shares in the offering. As a result, you should make your decision regarding the restructuring transaction assuming the number of shares to be sold and the initial public offering price could be as low as those referenced above.

        In connection with the initial public offering, the underwriters will have an option to purchase up to            additional shares of unrestricted common stock from CBOE Holdings. If the option is exercised in full, CBOE Holdings will receive approximately an additional $             million in net proceeds, assuming a public offering price of $            per share.

        CBOE Holdings intends to use the net proceeds from its initial public offering for general corporate purposes, including two possible concurrent tender offers for the outstanding Class A-1 and Class A-2 common stock. If the tenders offers are fully subscribed, CBOE Holdings anticipates that the aggregate net consideration for such offers will be approximately equal to the aggregate net proceeds of the initial public offering.

        Upon completion of the initial public offering, each outstanding share of Class A common stock and Class B common stock automatically shall be converted into one-half of one share of Class A-1 common stock and one-half of one share of Class A-2 common stock. As a result, assuming no shares are sold in the initial public offering by owners of CBOE Seats or Participating Group A Settlement Class Members, the owners of the CBOE Seats outstanding immediately prior to the restructuring transaction will own approximately 82% of the Class A-1 and Class A-2 common stock, and the Participating Group A Settlement Class Members will own approximately 18% of the Class A-1 and Class A-2 common stock outstanding following the restructuring transaction.

        Upon completion of the restructuring transaction, 2,489,039 shares of unrestricted common stock of CBOE Holdings will become available for issuance under the CBOE Holdings Long-Term Incentive Plan (the "Long-Term Incentive Plan"). In connection with, and effective upon, the restructuring transaction, directors, officers, and employees will be granted in the aggregate 2,240,552 shares of restricted stock that will be subject to vesting criteria described under "Compensation, Discussion and Analysis." After giving effect to the approved grants of restricted common stock to be made in connection with our Long-Term Incentive Plan, the percentage of total common stock issued and outstanding, immediately following the restructuring and prior to the closing of the initial public offering, regardless of class, held by CBOE Seat owners will be 80.02%, Participating Group A Settlement Class Members will be 17.57%, officers and other employees holding restricted stock under our Long-Term Incentive Plan will be 2.24% and directors holding restricted stock under the Long-Term Incentive Plan will be 0.17%.

        The Class A-1, Class A-2 and unrestricted common stock of CBOE Holdings will represent an equity ownership interest in CBOE Holdings and will have traditional features of common stock, including equal per share dividend, voting and liquidation rights. The rights of holders of CBOE Holdings common stock will be different from the rights of the CBOE members because the CBOE Holdings certificate of incorporation and bylaws in effect immediately after the restructuring transaction will be different from the governing documents of the CBOE. See "Comparison of Rights Prior to and After the Restructuring Transaction" on page 189 for a description of material differences.

        The CBOE Holdings common stock issued in the restructuring transaction, however, will not provide its holders with physical or electronic access to the CBOE's trading facilities. Following the restructuring transaction, physical and electronic access to the CBOE trading facilities, subject to such limitations and requirements as will be specified in the Rules of the CBOE, will be available to

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individuals and organizations that have obtained a trading permit from the CBOE. For more information regarding trading access following the restructuring transaction, please see "—Trading Permits" on page 57.

        If the restructuring transaction is approved by a majority of the CBOE memberships outstanding and entitled to vote, the Merger to effect the restructuring transaction will not be consummated until immediately prior to the closing of the initial public offering. This likely will not occur until approximately 30-60 days following the member vote. As such, the timing of the completion of the restructuring transaction is not certain and is dependent upon the timing of the closing of the initial public offering.

Background of the Restructuring Transaction

        Over the past several years, the CBOE has been faced with competition from both new and existing exchanges. Some of these competitors were established as for-profit exchanges, and others were converted from not-for-profit membership organizations to for-profit stock corporations. Along with changing their focus to that of a for-profit business, these demutualized exchanges typically have corporate and governance structures more like those of other for-profit businesses, which gives them greater flexibility in responding to the demands of the rapidly changing regulatory and business environment in which they conduct their activities. In addition, by being structured as stock, for-profit corporations, these other exchanges have opportunities to engage in business combinations and joint ventures with other organizations and to access capital markets in ways that are not available to non-stock membership corporations.

        In January 2005, responding to these changes, the CBOE's board of directors authorized the formation of a Business Model Task Force, or the Task Force, charged with the responsibility to develop a strategic plan that would respond to the challenges faced by the CBOE. Specifically, the Task Force was directed to consider the advantages and disadvantages of changing the business model of the CBOE to that of a for-profit business and making related changes to the ownership, corporate structure, and governance of the CBOE, possibly extending to the complete restructuring of the CBOE whereby it would be converted into a stock, for-profit corporation. The Task Force was directed to report its conclusions and recommendations to the full board.

        The Task Force consisted of four independent directors and three member directors and was chaired by James Boris, an independent director. Although the Task Force often met in executive sessions at which only its members were present, in conducting its review and analysis, the Task Force was assisted by the management of the CBOE and by Goldman, Sachs & Co. The Task Force obtained legal support from Schiff Hardin LLP, legal counsel to the CBOE, Richards, Layton & Finger, special Delaware legal counsel to the CBOE, and Sullivan & Cromwell LLP, special counsel to the CBOE in matters pertaining to the restructuring transaction.

        The Task Force held 12 formal meetings, beginning on February 17, 2005, and continuing until September 1, 2005. From the outset, the Task Force realized that any restructuring plan that it might recommend would have to deal with the valuation of the Exercise Right held by full members of the CBOT, pursuant to the CBOE's certificate of incorporation. Nevertheless, the Task Force determined it should first consider what changes to the structure, ownership and governance of the CBOE it would recommend before giving consideration to the Exercise Right.

        Accordingly, at its first few meetings the Task Force focused on how the CBOE should change its business model and how it should be organized and governed. Early in its deliberations, the Task Force concluded that formal changes to the corporate structure and ownership would take some time to put into effect, not only on account of the many steps required to accomplish this goal, but also because the implementation of these changes required that the Exercise Right be addressed. On the other hand, the Task Force also determined that several of the changes necessary to convert the CBOE to a for-profit business model could be put into effect prior to the time the CBOE would be in a position to

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implement a formal corporate restructuring. This determination was incorporated in the Task Force's preliminary recommendation made to the CBOE's board of directors at a meeting held on September 13 and 14, 2005. That recommendation included both near-term and long-term components.

        For the near term, the Task Force recommended that, effective January 1, 2006, the CBOE should adopt a "for-profit" business model to the extent compatible with its current corporate structure. Under such a business model, the CBOE would modify its governance and otherwise conduct its business activities with a focus on maximizing its profit potential in a manner consistent with the fulfillment of its responsibilities as a self-regulatory organization, even though it would not yet be structured as a for-profit stock corporation. For the longer term, the Task Force recommended that the CBOE should move forward with a program designed to provide for the restructuring of the CBOE by separating ownership of the Exchange from trading access and by changing the Exchange's corporate structure from that of a Delaware non-stock, corporation owned by its members to that of a Delaware stock, for-profit corporation that would be a subsidiary of a new Delaware stock, for-profit holding company owned by its stockholders.

        On September 14, 2005, at a regularly scheduled meeting, the CBOE's board of directors adopted these preliminary recommendations of the Task Force and directed the CBOE's management to proceed with the development of a detailed plan to implement both the near-term and long-term components of the recommendations. Specifically, management was directed to start transitioning to a for-profit business model commencing January 1, 2006, by addressing both the budgetary and governance implications of such a change. The board also directed the development of the necessary corporate documents and regulatory filings needed to implement the restructuring recommended by the Task Force. The board also encouraged management to engage in discussions with other organizations regarding transactions that might further the goals articulated by the Task Force and adopted by the board. The board requested that management present a business plan and budget at its January 26, 2006 meeting that reflected the transition to a for-profit business model, including adjustments to the CBOE's fee structure. Following the September 2005 board meeting, the CBOE engaged the Boston Consulting Group, or the BCG, to assist in a review of the CBOE's strategy. Over the next eleven weeks, the BCG worked with management on pricing strategy, overall strategy and change management.

        On October 27, 2005, at a regularly scheduled meeting of the board of directors of the CBOE, management reported to the board on the progress with respect to its plans to effect the conversion of the CBOE to a for-profit stock corporation and to start the transition to a for-profit operation beginning January 1, 2006.

        At the regularly scheduled board meeting of December 8, 2005, the BCG presented to the board the results of their eleven-week review of the CBOE relating to strategy, pricing and managing change. Following discussion, the board of directors reaffirmed the goal of unlocking value for its members through the conversion of the CBOE to a for-profit stock corporation with the transition to a for-profit model to start January 1, 2006. The board also approved several governance changes designed to streamline decision-making and enhance the efficiency of the advisory committees.

        On January 26, 2006, at a regularly scheduled meeting of the CBOE's board of directors, the board approved the business plan and budget proposed by management that addressed the strategic priorities established during the December 8, 2005 board meeting and began the transition to a for-profit business model. Management also proposed and the board adopted the creation of a Strategy and Implementation Task Force, or the SITF. The SITF consisted of five independent directors, the Vice Chairman, one floor director, the lessor director and a member firm director. Its role was to oversee the implementation of the CBOE's strategy with respect to its restructuring, including making recommendations to the board of directors regarding the details of the CBOE's demutualization. Management also established a demutualization team that would be responsible for developing an S-4 Registration Statement to be used in connection with such a restructuring.

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        The SITF had six formal meetings between March and July 2006, as well as a number of less formal discussions among its members. At these meetings, the task force addressed various aspects of the CBOE's demutualization, including the form the demutualization would take; the steps required to implement the demutualization; the consideration to be received by CBOE members; tax and accounting treatment; restrictions to be placed on the stock received by CBOE members; the centralization of access rights within the CBOE; how access would be granted after the demutualization; special petition rights for members prior to an initial public offering, if any; ownership and voting limitations; potential organized sales of CBOE Holdings stock; the form governance would take after demutualization; and the amendments required to the CBOE's Constitution and Rules. The Task Force was assisted in its deliberations by Goldman, Sachs & Co., Schiff Hardin, special legal counsel, Sullivan & Cromwell LLP, and special Delaware counsel, Richards, Layton & Finger. The results of these deliberations are reflected in the transaction proposed in this document.

        Over this same period of time, management also held discussions with several financial exchanges regarding potential transactions with the CBOE. These discussions included the potential for investments by the CBOE, the potential acquisition of other organizations by the CBOE and the potential acquisition of the CBOE by other organizations. Management was assisted in these explorations by the financial and legal advisors mentioned above. Ultimately, management did not recommend, and the board of directors did not pursue, any of these potential transactions.

        On March 23, 2006, at a regularly scheduled meeting of the board of directors of the CBOE, the board was briefed regarding the status of work on the restructuring transaction and was briefed by outside counsel regarding the registration process, the additional obligations that are applicable to registered companies, and various relevant provisions under the securities laws.

        On May 11, 2006, at a regularly scheduled meeting of the board of directors of the CBOE, management described and discussed with the Board the primary components of the then-contemplated restructuring transaction and post-demutualization structure, as well as the next steps in the process and key open issues.

        On July 27, 2006, at a regularly scheduled meeting of the CBOE board of directors, the SITF presented its recommendations regarding the demutualization of the CBOE. The board of directors approved the restructuring as recommended by the SITF, authorized the creation of CBOE Holdings and CBOE Merger Sub and authorized the preparation of an S-4 Registration Statement for purposes of implementing the demutualization of the CBOE. The board approved interim boards for CBOE Holdings and CBOE Merger Sub and authorized management to file an S-4 Registration Statement. The board also approved the creation of a Special Independent Directors Committee consisting of four independent directors (the "Special Committee"). The board delegated to the Special Committee the sole authority to determine the manner in which the membership interest held by Exercise Member Claimants and CBOE Seat owners would be converted into the right to receive the consideration to be received in any demutualization of the CBOE. The Board resolved not to approve or recommend any demutualization providing for a conversion of membership interests in the CBOE into other interests unless the consideration to be received in such transaction was consistent with the conversion of membership interests as determined by the Special Committee. The Special Committee was empowered to engage its own legal counsel and its own financial advisor to assist it in discharging these duties.

        Following the creation of the Special Committee at the July 27, 2006 board meeting through January 2007, the SITF met five times to consider open issues related to the restructuring transaction that had not been delegated to the Special Committee.

        On August 23, 2006, the Delaware Action was filed against CBOE and its directors regarding the planned demutualization of the CBOE. In the Delaware Action, the plaintiffs alleged that the CBOE board had already decided that the Exercise Member Claimants would not be entitled to the same consideration as other CBOE members in connection with the restructuring of the CBOE and sought a

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declaratory judgment and an injunction to require that any Exercise Member Claimant would be entitled to the same consideration as a CBOE Seat owner. The CBOE's position was that this suit was premature, as the Special Committee had not arrived at any conclusions regarding the consideration to be received by an Exercise Member Claimant.

        On September 28, 2006, at a regularly scheduled meeting of the CBOE board of directors, the board was briefed regarding the work on the restructuring transaction. At the request of the Special Committee, the Special Committee's charter was broadened to give the Special Committee the authority to determine whether any of the administrative or regulatory requirements that the CBOE's Rules impose upon persons who apply to become Exercise Member Claimants should be modified or waived in the event of a CBOE demutualization.

        On October 17, 2006, CME Holdings and CBOT Holdings announced that CME Holdings would acquire the CBOT through a merger of CBOT Holdings into CME Holdings. Because of the significant changes to the structure and ownership of the CBOT, and to the rights of CBOT members, that would result from the completion of this proposed transaction, its announcement required the CBOE board to consider the possible impact of the proposed CME/CBOT Transaction on the eligibility of CBOT members to become and remain members of the CBOE pursuant to the Exercise Right.

        On December 12, 2006, at a regularly scheduled meeting of the board of directors of the CBOE, lawyers from the CBOE's outside legal counsel, Schiff Hardin, presented a legal analysis of the impact of the CME/CBOT Transaction on the Exercise Right. Following a discussion from which members of the Special Committee were recused, the board determined that CBOT would no longer have "members" as contemplated by Article Fifth(b) upon the completion of the CME/CBOT Transaction and authorized CBOE management to submit a rule filing to the SEC consisting of (1) an interpretation of Article Fifth(b) in a manner consistent with the board's determination and (2) authorization for the CBOE, upon completion of the CME/CBOT Transaction, to grant temporary access to CBOT members who had exercised and were in good standing as members of the CBOE on December 11, 2006, to the extent and for the period of time necessary to avoid disruption to the CBOE's market as a result of the ineligibility of such persons to maintain the status of members of CBOE pursuant to the Exercise Right. The CBOE submitted this rule filing on December 12, 2006, and amended it on January 17, 2007. This rule filing is sometimes referred to as the "Eligibility Rule Filing."

        Following the approval of this action, the directors on the Special Committee were invited to rejoin the meeting and were informed of the board's decision. The Special Committee informed the board that, based on the board's interpretation of the impact of the proposed CME/CBOE Transaction on the Exercise Right and based on the board's understanding that the CME/CBOT Transaction would likely close prior to the demutualization of the CBOE, the Special Committee would defer further deliberations until such time as it became appropriate to either reinitiate the Special Committee's deliberations, terminate the Special Committee's existence, or take such other action as was warranted.

        On January 4, 2007, the CBOT and the other plaintiffs in the Delaware Action filed an amended complaint that challenged the interpretation of Article Fifth(b) contained in the SEC Eligibility Rule Filing. On January 11, 2007, plaintiffs filed a motion for summary judgment on their claims. In addition to continuing to assert their claims about the amount of consideration to which Exercise Member Claimants would be entitled as part of the CBOE restructuring transaction, plaintiffs sought a declaratory judgment and an injunction to prevent the CBOE from implementing the interpretation of Article Fifth(b) that the CBOE had filed with the SEC in the Eligibility Rule Filing. On January 16, 2007, CBOE and the director defendants moved to dismiss the amended complaint to the extent it challenged CBOE's interpretation of Article Fifth(b), on the ground that the SEC's jurisdiction to consider such interpretations preempts any state law challenge to that interpretation. In their motion, the defendants further moved to stay consideration of plaintiffs' claims regarding the consideration to

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which Exercise Member Claimants otherwise would be entitled until it was known whether the CME/CBOT Transaction would close before CBOE's restructuring.

        On January 25, 2007, at a regularly scheduled meeting of the CBOE board of directors, management made a presentation describing the restructuring transaction. The board approved the proposed terms of the restructuring transaction and authorized the board of CBOE Holdings to file the Registration Statement, of which this proxy statement and prospectus is a part, with the SEC.

        On March 15, 2007 the Intercontinental Exchange (ICE) made an unsolicited bid to acquire the CBOT in competition with the CME/CBOT Transaction. ICE approached CBOE regarding a potential joint proposal which would be designed to resolve the Exercise Right issue as part of an ICE acquisition of the CBOT. On May 30, 2007, CBOE and ICE announced that they had entered into an exclusive agreement in which each full member of the CBOT holding an Exercise Right would be entitled to receive $500,000 in cash and/or debt securities convertible into the stock of a newly created CBOT/ICE Holdings in exchange for relinquishing the Exercise Right. The agreement was contingent upon the closing of the proposed merger of ICE and CBOT Holdings.

        In June 2007, the CBOT Holdings board recommended and the stockholders approved the CME/CBOT Transaction. The CME/CBOT Transaction closed on July 12, 2007.

        On June 29, 2007, to address issues raised by the CME/CBOT Transaction, the CBOE board approved an interpretation of CBOE Rule 3.19, which provided that persons who were exerciser members in good standing before the consummation of the CME/CBOT Transaction would temporarily retain their CBOE membership status until the SEC ruled on the Eligibility Rule Filing. We refer to this interpretation as the "Interim Access Interpretation." The CBOE filed the Interim Access Interpretation with the SEC on July 2, 2007, and it went into effect upon its filing.

        On July 20, 2007, CBOT and the other plaintiffs filed a motion requesting that the Delaware Court enter a temporary restraining order prohibiting CBOE from implementing or enforcing the Interim Access Interpretation. On August 3, 2007, the Court denied the motion for a temporary restraining order.

        On August 28, 2007, the CBOE board of directors approved a second interpretation of CBOE Rule 3.19, which provided that the persons who temporarily retained their CBOE membership status pursuant to the Interim Access Interpretation would continue to retain that status after the SEC approved the Eligibility Rule Filing until other specified events occurred. We refer to this interpretation as the "Continued Membership Interpretation." The Continued Membership Interpretation was filed with the SEC on September 10, 2007 and was effective on filing.

        On January 15, 2008, the SEC approved the Eligibility Rule Filing and CBOE's interpretation that CBOT "no longer had 'members' as contemplated by Article Fifth(b) following the completion of the CME/CBOT Transaction."

        On February 6, 2008, the plaintiffs in the Delaware Action filed their third amended complaint. Plaintiffs' essential claims remained the same, although plaintiffs alleged in their new complaint that the adoption of the Interim Access Interpretation damaged so-called CBOT full members in their capacity as owners and lessors of such memberships and that CBOE's board of directors was dominated by interested directors when it approved the Eligibility Rule Filing, the Interim Access Interpretation and the Continued Membership Interpretation.

        On March 14, 2008, CBOT and two CBOT members appealed to the United States Court of Appeals for the District of Columbia from the SEC order that approved the Eligibility Rule Filing and CBOE was granted leave to intervene in that appeal.

        During the fall of 2007 and into spring 2008, CBOE and plaintiffs' counsel engaged in periodic settlement discussions. On June 2, 2008, two days before the Delaware Court was to hear argument on the parties' pending motions for summary judgment, the parties entered into an agreement in principle

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to settle both the Delaware Action and the appeal from the SEC order pending in the federal Court of Appeals. On July 24, 2008, CBOE's board of directors approved the material terms of the Settlement Agreement as then presented to the board and authorized the Office of the Chairman to finalize the Settlement Agreement. On August 20, 2008, the parties entered into the Settlement Agreement, and that agreement was preliminarily approved by the Delaware Court on August 22, 2008. On August 22, 2008, CBOE held an informational membership meeting regarding the Settlement Agreement. On September 17, 2008, CBOE's members approved the Settlement Agreement.

        On December 16, 2008, the Delaware Court conducted a lengthy hearing to consider whether to approve the Settlement Agreement and to consider the objections to the settlement.

        On May 6, 2009, CBOE board of directors approved certain changes to the restructuring transaction and certain changes to the proposed post-demutualization certificate of incorporation of CBOE Holdings.

        On June 3, 2009, the Delaware Court entered an order approving the Settlement Agreement, while reserving ruling on whether certain objectors were eligible to participate in that settlement. After subsequently ruling on those objections, the Delaware Court, on July 29, 2009, entered an order of approval and final judgment approving the Settlement Agreement, resolving all open issues about the settlement and dismissing the Delaware Action. Five appeals from the order of approval and final judgment (brought on behalf of eight appellants) were filed with the Delaware Supreme Court. In addition to the appeals, one individual filed a post-judgment motion with the Delaware Court arguing that he should be allowed to participate as a Participating Group A Settlement Class Member, and that motion was granted.

        On November 30, 2009, the CBOE entered into a settlement of all appeals from the Delaware Court's order of approval and final judgment. Pursuant to that settlement, a stipulation to dismiss all of the appeals was filed on November 30, 2009, and all other parties to the appeals consented to that stipulation. On December 2, 2009, the Delaware Supreme Court entered an order dismissing the appeals. Upon the Delaware Supreme Court's order, the Delaware Court's July 29, 2009 order of approval and final judgment became final, and that order and judgment is no longer subject to appeal.

        On December 4, 2009, CBOT and the two CBOT members that appealed to the United States Court of Appeals for the District of Columbia from the SEC order that approved the Eligibility Rule Filing voluntarily dismissed their appeal. As a result, the SEC's January 15, 2008 order approving the Eligibility Rule Filing is no longer subject to appeal.

        At the end of 2009, the CBOE and CBOE Holdings boards of directors began to explore the possibility of pursuing an initial public offering of CBOE Holdings' unrestricted common stock concurrently with the restructuring transaction. At their meetings in December 2009, the CBOE and CBOE Holdings boards of directors continued to investigate and had general discussions of this possible public offering, including the mechanics of such a transaction and its potential benefits.

        At a meeting of the CBOE and CBOE Holdings boards of directors held on March 4, 2010, the boards met with members of senior management, CBOE's legal counsel and Goldman, Sachs & Co. At that meeting, the boards of directors considered and unanimously approved, among other things, the structure of the restructuring transaction, proceeding with a concurrent initial public offering of unrestricted common stock of CBOE Holdings, upon which the completion of the restructuring transaction will be contingent, and the filing of registration statements with the SEC in connection with the restructuring transaction and initial public offering. The CBOE Holdings board of directors also approved the structure of a dividend committee for the purpose of declaring a special dividend of $1.67 per share of Class A and Class B Common Stock or $100,200 per CBOE Seat and $23,513.60 per Group A Package, to be paid immediately following the restructuring transaction and the issuance of stock pursuant to the Settlement Agreement and prior to the closing of the initial public offering. The CBOE board also unanimously recommended that the members approve the restructuring transaction.

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On April 12, 2010, the CBOE Holdings Executive Committee recommended an increase in the number of shares to be issued for each CBOE Seat, which would effectively reduce the dividend per share to $1.25 per share, or $100,000 per CBOE Seat and $23,467.50 per Group A Package.

The CBOE's Reasons for the Restructuring Transaction

        In approving the restructuring transaction, the CBOE board of directors considered a number of factors, including the ones discussed in the following paragraphs. In light of the number and wide variety of factors considered in connection with its evaluation of the transaction, the CBOE board of directors did not consider it practicable to, and did not attempt to, quantify or otherwise assign relative weights to the specific factors it considered in reaching its determination. The CBOE board viewed its position as being based on all of the information available and the factors presented to and considered by it. In addition, individual directors may have given different weight to different factors. This explanation of the CBOE's reasons for the proposed restructuring transaction and all other information presented in this section is forward-looking in nature and, therefore, should be read in light of the factors discussed under "Forward-Looking Statements" on page 35.

        In reaching its decision, the CBOE board of directors consulted with the CBOE management with respect to strategic, operational and regulatory matters, as well as with its outside legal counsel and financial advisors and the board's special counsel.

        The CBOE board of directors believes that changing the CBOE's focus to that of a for-profit business, along with modifying the CBOE's corporate and governance structures to be more like those of other for-profit businesses, will provide the CBOE with greater flexibility to respond to the demands of a rapidly changing business environment. By being structured as a stock, for-profit corporation, the CBOE will be able to pursue strategic opportunities to engage in business combinations and joint ventures with other organizations and to access capital markets in ways that are not available to non-stock, membership corporations. As a stock corporation, ownership will be separated from access. Stock will provide a "currency" separate from access that can be used in acquisitions and mergers. Furthermore, our stock will give us the ability to raise capital through stock issuances. We believe that the restructuring transaction will move us one step closer to achieving our key objectives of providing our owners a more liquid investment.

        The CBOE board of directors also believes that the restructuring of the CBOE will enable the CBOE to enhance its competitiveness with other options exchanges, including both open outcry and electronic markets, while preserving the CBOE's ability to provide trading opportunities and benefits to our members. The proposed changes in our structure will streamline the governance and decision-making process, which will allow us to respond more quickly to changes in the competitive environment. In addition, our for-profit structure will remove ambiguity with respect to objectives and priorities and establish stockholder interest as the primary guidepost for decision making. At the same time, our new structure will allow us to provide trading access through trading permits, which will be issued by the Exchange. See "—Trading Permits" on page 57 for a discussion of this access. This shift in how access is granted will also alter how we think of the users of our marketplace. Users, as distinct from owners, will become customers of the CBOE. It will be clear that the interest of stockholders is served by providing trading opportunities and other benefits to these customers in a way that prompts them to continue to prefer the CBOE to alternative marketplaces. The CBOE board believes that the restructuring transaction will allow the CBOE to:

•

maximize the value of the CBOE's business by adopting a for-profit approach to business with a view towards increasing volume, efficiency and liquidity in the markets it provides;



•

increase the CBOE's ability to respond more efficiently to changes within the industry, markets and regulations that govern the CBOE through a more streamlined governance and decision-making structure, including a possible reduction in the size of the board and a reduction in the number of member committees;

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•

increase the CBOE's flexibility to diversify and expand its business;



•

segregate more easily the CBOE's different lines of business into separate subsidiaries through a holding company structure, which could provide greater flexibility in administration and allow these subsidiaries to focus more effectively on particular markets, products or services; and



•

distribute profits from the operation of its business to its stockholders as determined by its board of directors and as permitted by applicable law.

        As such, the restructuring transaction is designed to:

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facilitate CBOE Holdings' engagement in other businesses that are either unregulated, or are regulated differently from the CBOE's current business;



•

provide greater flexibility to finance, acquire or dispose of individual businesses;



•

create a framework to facilitate public markets for equity securities of CBOE Holdings, capital-raising transactions and other securities issuances, such as the issuance of securities as consideration in an acquisition or merger; and



•

satisfy the SEC's current policy that at least 20% of the board of the CBOE should be selected by the members, while providing flexibility in governance at the holding company level.

        The CBOE board also considered the following potentially negative factors associated with the restructuring transaction:

•

the possibility that regulatory or governmental authorities might seek to impose conditions on or otherwise prevent or delay the restructuring transaction;



•

the risks and costs to the CBOE if the restructuring transaction is not completed, including the potential diversion of management and employee attention, potential employee attrition and the potential effect on business and customer relationships;



•

the risk that the potential benefits of the restructuring transaction may not be fully or partially realized;



•

the risk of diverting management focus and resources from other strategic opportunities and from operational matters and potential disruption associated with the restructuring transaction;



•

the risk that CBOE members entitled to vote may fail to approve the restructuring transaction;



•

the fees and expenses associated with completing the transaction; and



•

various other risks associated with the restructuring transaction described under "Risk Factors."

        The CBOE and CBOE Holdings boards have considered the advantages and disadvantages of the initial public offering. In particular, the CBOE and CBOE Holdings boards discussed the following considerations:

•

The initial public offering would enable CBOE members, who would become CBOE Holdings stockholders, to own shares of common stock that are traded on a public market.



•

CBOE Holdings stockholders would be able to increase or decrease their ownership interest in CBOE Holdings through open market purchases and sales.



•

As a publicly-traded company, CBOE Holdings would be able to finance capital improvements and business activities to pursue its commercial objectives through subsequent offerings of its common stock.



•

The initial public offering would improve financing alternatives for CBOE Holdings and, therefore, for the CBOE business.

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•

The initial public offering would enable CBOE Holdings to use common stock to acquire new businesses, companies and products that could strengthen its competitive position in the marketplace.



•

With the ability to provide equity incentive compensation, such as stock options and restricted stock, CBOE Holdings would be better able to recruit, develop and retain qualified employees and management while preserving its cash resources.



•

CBOE Holdings may be more likely to be the target of an unsolicited takeover attempt.



•

It will be more costly to operate the business as a public corporation.

Alternatives to the Restructuring Transaction

        In considering the restructuring transaction, the CBOE board of directors also considered a number of strategic alternatives available to the CBOE, including:

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remaining a not-for-profit, non-stock membership corporation;



•

converting to a for-profit, non-stock corporation;



•

pursuing one or more acquisitions of or by other U.S. or non-U.S. exchanges; and



•

exploring mergers, alliances and joint ventures with other entities.

        The CBOE board of directors believed and continues to believe that these potential risks and drawbacks are outweighed by the potential benefits that the CBOE board expects the CBOE and its members to achieve as a result of the proposed restructuring transaction.

Initial Public Offering

        The principal reasons for the initial public offering are to increase our financial strength through improved access to capital and to provide a liquid market for our owners. In addition, access to capital will provide us with greater strategic flexibility. Conducting an initial public offering concurrently with the restructuring transaction, will also provide more liquidity to our members for their interests in CBOE than if CBOE were to complete the restructuring transaction without completing such an initial public offering.

        CBOE Holdings currently expects to offer approximately            shares of its unrestricted common stock following the requisite approval of the restructuring transaction by CBOE members. In addition, CBOE Holdings intends to permit all holders of the Class A and Class B common stock with the opportunity to sell in the initial public offering a small portion of the shares of Class A and Class B shares to be received in the restructuring transaction and pursuant to the Settlement Agreement. The shares of Class A and Class B common stock to be sold by these selling stockholders will be converted into shares of our unrestricted common stock prior to being sold in the initial public offering. The actual number of shares to be offered and sold and the price at which such shares will be offered and sold in the initial public offering may be different than the assumptions provided herein, and the final decision about offering parameters will be determined by the CBOE Holdings board of directors.

         We may proceed with the restructuring transaction and the initial public offering without seeking additional member approval only if CBOE Holdings can complete the initial public offering at a price per share of at least $            and by CBOE Holdings selling at least                  shares in the offering. As a result, you should make your decision regarding the restructuring transaction assuming the number of shares to be sold and the initial public offering price could be as low as those referenced above.

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        Upon the completion of the initial public offering, each outstanding share of Class A common stock and Class B common stock automatically shall be converted into one-half of one share of Class A-1 common stock and one-half of one share of Class A-2 common stock. As a result, assuming no shares are sold in the initial public offering by owners of CBOE Seats or Participating Group A Settlement Class Members, the owners of the CBOE Seats outstanding immediately prior to the restructuring transaction will own approximately 82% of the Class A-1 and Class A-2 common stock, and the Participating Group A Settlement Class Members will own approximately 18% of the Class A-1 and Class A-2 common stock outstanding following the restructuring transaction and the completion of the initial public offering.

        Upon completion of the restructuring transaction, 2,489,039 shares of unrestricted common stock of CBOE Holdings will become available for issuance under the Long-Term Incentive Plan. In connection with, and effective upon, the restructuring transaction, directors, officers, and employees will be granted in the aggregate 2,240,552 shares of restricted stock that will be subject to vesting criteria described under "Compensation, Discussion and Analysis." After giving effect to the approved grants of restricted stock to be made in connection with our Long-Term Incentive Plan, the percentage of total common stock issued and outstanding immediately following the restructuring and prior to the initial offering, regardless of class, held by CBOE Seat owners will be 80.02%, Participating Group A Settlement Class Members will be 17.57%, officers and other employees holding restricted stock will be 2.24% and directors holding restricted stock will be 0.17%.

        Giving effect to the initial public offering and the approved grants of restricted common stock to be made in connection with our long-term incentive plan, and assuming              shares of unrestricted stock are sold in the initial public offering, none of which are sold by owners of CBOE Seats and Participating Group A Settlement Class Members, the percentage of total common stock issued and outstanding, regardless of class, held by CBOE Seat owners will be            %, Participating Group A Settlement Class Members will be             %, holders of restricted shares under our long-term incentive plan will be            % and purchasers in the initial public offering will be            %.

Conditions to Completion of the Restructuring Transaction

        In order for us to complete the restructuring transaction, the following approvals and conditions, among others, must be obtained and/or satisfied:

        Approval by Our Members.     To complete the restructuring transaction, we must obtain the approval of a majority of all of the CBOE memberships outstanding and entitled to vote. Please see a description of the CBOE special meeting on page 38.

        Initial Public Offering.     The restructuring transaction is contingent on the concurrent completion by CBOE Holdings of an underwritten initial public offering of its unrestricted common stock as discussed above under "Initial Public Offering." CBOE Holdings will, in the sole discretion of its board of directors, determine the number of shares to be issued in the initial public offering and the price at which such shares will be sold. Such terms and parameters may differ from those assumptions set forth in this proxy statement and prospectus.

What You Will Receive in the Restructuring Transaction

        CBOE Seat Owners.     In the restructuring transaction, each CBOE Seat existing on the date of the restructuring transaction will immediately be converted into 80,000 shares of Class A common stock of CBOE Holdings.

        Group A Participating Settlement Class Members.     Each Participating Group A Settlement Class Member will be issued, immediately following the effectiveness of the Merger effecting the

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restructuring transaction and as required by the Settlement Agreement, 14,080 shares of Class B common stock of CBOE Holdings for each Group A Package approved by the Delaware Court.

        Immediate Conversion of Shares of Class A and Class B Common Stock into Shares of Class A-1 and Class A-2 Common Stock as a result of the Initial Public Offering.     Upon completion of the initial public offering, each outstanding share of Class A common stock and Class B common stock automatically shall be converted into one-half of one share of Class A-1 common stock and one-half of one share of Class A-2 common stock. Because the initial public offering is anticipated to close concurrently with the completion of the restructuring transaction, both the Class A common stock issued in the restructuring transaction to CBOE Seat owners and the Class B common stock issued to Participating Group A Settlement Class Members pursuant to the Settlement Agreement will convert into shares of Class A-1 and Class A-2 common stock shortly following their respective issuances. The Class A-1 and A-2 common stock shall have all the same rights and privileges as the Class A common stock; however, the Class A-1 and A-2 common stock will be issued subject to certain transfer restrictions that will apply for different durations following the initial public offering. For a description of these transfer restrictions, please see below.

        Transfer Restrictions on CBOE Holdings Class A and Class B Common Stock.     The board of directors of CBOE Holdings has determined to proceed with an initial public offering of its unrestricted common stock concurrently with the completion of the restructuring transaction. As a result, the shares of Class A and Class B common stock issued in the restructuring transaction and pursuant to the Settlement Agreement, respectively, and not converted into unrestricted common stock for purposes of being sold in the initial public offering, will convert into shares of Class A-1 and Class A-2 common stock shortly following their issuance. The CBOE Holdings board of directors has determined not to appoint any agent or to allow market trading of the Class A or Class B shares. As a result, the shares of Class A and Class B common stock will not be transferable in any manner and will convert automatically into shares of Class A-1 and Class A-2 common stock and become subject to the transfer restrictions discussed below.

        Transfer Restrictions on the CBOE Holdings Class A-1 and Class A-2 Common Stock.     The Class A-1 and Class A-2 common stock will be subject to the transfer restrictions or "lock-up restrictions" under CBOE Holdings' certificate of incorporation. These lock-up restrictions will expire on the Class A-1 and Class A-2 common stock as of the 180 ^th and 360 ^th  day, respectively, following the closing date of the initial public offering. During each applicable lock-up period, shares of CBOE Holdings Class A-1 or Class A-2 common stock may not be directly or indirectly assigned, offered for sale, sold, transferred or otherwise disposed of, except pursuant to limited exceptions set forth in the CBOE Holdings certificate of incorporation, which provides for certain permitted transfers to affiliates, family members, qualified trusts and estates, as well as certain pledges and the potential transfer upon a bona fide foreclosure resulting therefrom under the circumstances set forth in CBOE Holdings' certificate of incorporation. Subject to possible extension in the event of an organized sale, as more fully set forth in this proxy statement and prospectus, upon the expiration of the applicable lock-up period with respect to the Class A-1 and Class A-2 common stock, such shares then scheduled to expire would automatically convert to unrestricted common stock that would be freely transferable.

        Pursuant to Article Fifth(d)(i) of CBOE Holdings' Certificate of Incorporation, the board of directors of CBOE Holdings will remove the transfer restrictions associated with any shares of Class A or Class B common stock to be sold by owners of CBOE Seats and Participating Group A Settlement Class Members in the initial public offering and convert such shares into shares of CBOE Holdings' unrestricted common stock. Moreover, the board of directors of CBOE Holdings will remove the transfer restrictions associated with any shares Class A-1 and Class A-2 common stock to be purchased by CBOE Holdings in the proposed tender offers.

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        In addition to the restrictions described above, all shares of Class A-1 and Class A-2 common stock must be registered in the name of the owner and may not be registered in the name of any nominee or broker. The shares of Class A-1 and Class A-2 common stock will not have any value for margin or net capital purposes until such shares convert to unrestricted common stock and are freely tradeable.

Who Will Receive the Restructuring Consideration

        The owner of each CBOE Seat will be issued CBOE Holdings Class A common stock in the restructuring transaction as described in this proxy statement and prospectus. These shares of Class A common stock will convert into shares of Class A-1 and Class A-2 common stock automatically upon the closing of the initial public offering. On the other hand, because we permit owners of CBOE Seats to lease their seats to other persons, it is possible that more than one person may have an interest in the same seat. For instance, during the term of a lease, the lessee is considered to be a member of the CBOE for trading purposes, although, under Delaware law, the owner of the CBOE Seat (or lessor) retains the equity right represented by the CBOE membership and is the member of the CBOE for purposes of ownership. The CBOE Holdings Class A common stock being issued in the restructuring transaction represents an equity interest in CBOE Holdings that is being issued in exchange for the former CBOE member's equity interest in the CBOE. The CBOE Holdings Class A common stock, therefore, will be issued to the owner of the CBOE Seat and not a lessee of a seat.

        As a result of the approval by the SEC of the Eligibility Rule Filing and the Delaware Court's approval of the Settlement Agreement becoming final, there are no longer members of the CBOT who qualify to become or remain a member of the CBOE under Article Fifth(b). Accordingly, at the time of the restructuring transaction, there will be no exercise memberships outstanding to be converted in the restructuring transaction. The Participating Group A Settlement Class Members and Participating Group B Settlement Class Members as defined herein will not receive any consideration in the restructuring transaction or in the Merger effecting the restructuring transaction. The CBOE has agreed, pursuant to the Settlement Agreement, to make available a pool of Class B common stock to be paid to the Participating Group A Settlement Class Members. In addition, the CBOE has agreed to make available a pool of cash to be paid to the Participating Group A and Participating Group B Settlement Class Members. The Participating Group A Settlement Class Members and the Participating Group B Settlement Class Members will receive the settlement consideration described below pursuant to the terms of the Settlement Agreement and only immediately after the Merger effecting the restructuring transaction is complete. The shares of Class B common stock issued to the Participating Group A Settlement Class Members will convert into shares of Class A-1 and Class A-2 common stock automatically upon the closing of the initial public offering. For a discussion of the Settlement Agreement, please see "—Exercise Right Settlement Agreement" on page 64.

Payment of Special Dividend

        The CBOE Holdings board of directors has appointed a special committee for purposes of declaring a special dividend and has authorized the special committee to declare a dividend of $1.25 per share of Class A and Class B common stock. The special dividend will be paid on the Class A and Class B common stock outstanding immediately following the completion of the restructuring transaction and the issuance of Class B common stock pursuant to the Settlement Agreement and will be paid immediately prior to the completion of the initial public offering. The committee may not declare or pay the special dividend unless the restructuring transaction is approved by a majority of the CBOE memberships entitled to vote and the Merger has been completed. As a result of the special dividend, each CBOE Seat owner will receive $100,000 in respect of each CBOE Seat such member owns, and each Participating Group A Settlement Class Member will recieve $23,467.50 for each Group A Package approved by the Delaware Court.

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Tender Offers

        CBOE Holdings currently intends to make two tender offers, one for its shares of Class A-1 common stock and one for its shares of Class A-2 common stock. It is currently expected that each offer will be commenced between the 60 ^th and 120 ^th day after the closing of the initial public offering, and each will be conducted concurrently. It is expected that each offer will be made for the same aggregate dollar amount. CBOE Holdings anticipates that the aggregate dollar amount of the two tender offers, if fully subscribed, would roughly approximate the net proceeds of the initial public offering. We currently expect the price per share offered in the tender offers will approximate the prevailing market price for the unrestricted common stock at the time the offers are commenced. The timing and terms of each tender offer, including the price per share offered, however, are subject to the discretion of the CBOE Holdings board of directors. The purpose of the tender offers is both to provide liquidity to former owners of CBOE Seats during the term of the transfer restrictions associated with the shares of Class A-1 and A-2 common stock and to reduce the number of shares of our common stock outstanding following the restructuring transaction and this offering. Although it is CBOE Holdings' intention to complete the tender offers as described above, the CBOE Holdings board of directors may determine not to launch, or to reduce the size of, the tender offers as a result of market conditions, our operating results or outlook or other developments following the initial public offering. As such, there can be no assurance that the tender offers will occur at all or as described in this proxy statement and prospectus.

Organized Sales

        CBOE Holdings will have the right to conduct organized sales of the Class A-1 and A-2 common stock of CBOE Holdings when the transfer restriction period applicable to the shares of Class A-1 and A-2 common stock of CBOE Holdings is scheduled to expire. The purpose of this right is to enable CBOE Holdings to facilitate a more orderly distribution of its common stock into the public market. If CBOE Holdings elects to conduct an organized sale, no shares of the Class A-1 or A-2 common stock of CBOE Holdings for which transfer restrictions are scheduled to lapse may be sold during the applicable transfer restriction period, which may be extended to the extent such organized sale is still being conducted, except as part of the organized sale or in a permitted transfer. Holders of the Class A-1 or A-2 common stock may elect to participate in such organized sale but are not required to do so.

        If CBOE Holdings completes an organized sale, no shares of the Class A-1 or A-2 common stock of CBOE Holdings for which transfer restrictions are scheduled to lapse may be sold until the 91st day after the later of the expiration of the related transfer restriction period and the completion of the organized sale, except as part of the organized sale or in a permitted transfer.

        For a discussion of organized sales and the procedures to be followed in the event CBOE Holdings determines to conduct an organized sale, please see "Description of CBOE Holdings Capital Stock—Organized Sales" on page 181.

Effect of the Restructuring Transaction on Trading Access

        In the restructuring transaction, all memberships in the CBOE and the trading rights they represent will be cancelled when the CBOE Seats are converted into shares of Class A common stock of CBOE Holdings. The CBOE Holdings common stock issued in the restructuring transaction will not provide the holder with any right to have physical or electronic access to the CBOE's trading facilities. Following the restructuring transaction, physical and electronic access to the trading facilities of the CBOE, subject to such limitations and requirements as will be specified in the Rules of the CBOE, will be available to individuals and organizations that have obtained a trading permit from the CBOE. For more information regarding trading access following the restructuring transaction, please see

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"—Trading Permits" below. In addition, effective upon completion of the restructuring transaction, each lease of a CBOE Seat will be voided, by operation of law or rule, and the lessee members will cease to have any trading rights under the lease after termination. Members who currently lease their seats, however, will have the opportunity to apply for a trading permit following the restructuring transaction. In addition, CBOE Temporary Members and holders of interim trading permits immediately prior to the restructuring transaction will have the opportunity to apply for a trading permit on the same terms and conditions as are offered to owners of CBOE Seats. See "Trading Permits" below.

        In the restructuring transaction, all CBOE Seats existing on the date of the restructuring transaction will be converted into CBOE Holdings Class A common stock, and the concept of a "member" of the CBOE under Delaware law (i.e., as a holder of equity) will cease to exist. The concept of "member" and "member organizations" of the CBOE for purposes of the Exchange Act, however, will continue to exist after the restructuring transaction (generally including individuals and organizations that have direct access to the CBOE as a result of obtaining a trading permit in the CBOE). Such individuals or organizations, however, will not, by virtue of being a "member" for purposes of the Exchange Act, be an equity owner of CBOE Holdings or any of its subsidiaries. Instead, such individuals and organizations will hold trading permits at the CBOE and, therefore, will be subject to the Rules and policies of the CBOE. Following the restructuring transaction, we will refer to these individuals and organizations as "Trading Permit Holders."

Trading Permits

        Trading Permits Following the Restructuring Transaction.     Prior to the date of the restructuring transaction, the CBOE will conduct an application process for post-restructuring trading permits in accordance with procedures to be established by the CBOE. The CBOE will notify the membership of these procedures prior to the commencement of the application process.

        •     Eligible Applicants. Any person or firm that is a member, CBOE Temporary Member or interim trading permit holder with trading privileges on the CBOE and any person or firm approved for membership and eligible to have trading privileges on the CBOE may apply for one or more post-restructuring trading permits in the initial application process.

        •     Applicants Guaranteed to Receive Initial Trading Permits. Provided an applicant is in good standing as of the date of the restructuring transaction and complies with the application procedures established by the CBOE, the applicant will be guaranteed to receive a trading permit immediately following the restructuring transaction for:

(1)

each membership not subject to an effective lease as of the date of the restructuring transaction that is owned by the applicant;



(2)

each membership that is leased by the applicant as a lessee as of the date of the restructuring transaction;



(3)

each trading permit issued by the CBOE prior to the restructuring transaction that is held by the applicant; and



(4)

each temporary membership that is held by the applicant.

        Accordingly, every individual or firm with trading privileges on the CBOE that is in good standing with the CBOE immediately prior to the restructuring transaction will be entitled, by obtaining a permit as described above, to continue to have access to the trading facilities of the CBOE immediately following the restructuring transaction in substantially the same manner that they currently have, provided they continue to meet the requirements for access. An individual or firm that is guaranteed to receive a trading permit immediately following the restructuring transaction that does not apply to receive a new permit at the time of the restructuring transaction

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will not receive any priority if the individual or firm should return and seek a permit at a later date.

        Lessors with memberships that are subject to an effective lease as of the date of the restructuring transaction will not be guaranteed to receive a post-restructuring trading permit, and a lessor will not be eligible to apply for post-restructuring trading permits unless that lessor is eligible to have trading privileges on the CBOE.

        •     Allocation of Remaining Initial Trading Permits. In the event there are trading permits available after the allocation of permits pursuant to the guarantee described above, those remaining trading permits may be allocated to applicants through a random lottery process. Applicants for these remaining trading permits may include persons or firms that are guaranteed to receive one or more initial trading permits and which have applied for a greater number of initial trading permits than they are guaranteed to receive, as well as any applicants that were not guaranteed to receive initial trading permits. Each of the remaining applicants together with its affiliates shall be eligible to receive no more than the greater of 10 permits or 20% of the initial trading permits allocated through the random lottery process, if the demand for initial trading permits exceeds the available number.

        •     Types of Trading Permits. The CBOE may issue different types of trading permits for different purposes. For example, permits may differ based on whether the holder is a market maker, floor broker or order flow providing firm. Permits may also vary based on the product being accessed or other factors that the CBOE determines in the future.

        The initial types of trading permits that CBOE currently plans to issue following the restructuring transaction are a market maker permit, a floor broker permit, an electronic access permit, and a CBSX permit. The market maker permit would be available to market makers (including market makers trading remotely), designated primary market makers (DPMs), electronic DPMs, and lead market makers. Market maker permit holders would also be able to purchase additional bandwidth for their electronic quoting operations above the allowance provided by their market maker permits. The floor broker permit would be available to floor brokers requiring physical access to the trading floor. The electronic access permit would be available to clearing firms, firms approved to transact business with the public, and order service firms. CBSX permits are described below. These initial permit types remain subject to change and any changes in permit types would be announced prior to becoming effective.

        •     CBSX Trading Permits. The initial CBOE trading permits will grant the holder the ability to effect transactions on both CBOE and CBSX, as is the case with current CBOE memberships. CBOE will also make available post-restructuring CBSX trading permits that provide the ability to effect transactions solely on CBSX. If an applicant receives an initial CBOE trading permit, such applicant will not need to obtain a CBSX trading permit to have trading privileges on CBSX. CBSX trading permits will be made available through the same application process that will be used for CBOE trading permits and each current holder of a CBSX trading permit will be guaranteed to receive a post-restructuring CBSX trading permit through that application process, provided the applicant is in good standing as of the date of the restructuring transaction and complies with the application procedures established by the CBOE.

        •     Number of Trading Permits. As of December 31, 2009, CBOE had 1,047 authorized memberships consisting of 930 CBOE Seats, 67 CBOE Temporary Members, and 50 interim trading permits (38 of which were in use on December 31, 2009). There were also 97 CBOE members with trading access to CBSX and 62 CBSX trading permit holders as of December 31, 2009. It is currently expected that not fewer than 1,025 permits will be made available at the time of the restructuring transaction. The CBOE also will have the ability to increase, decrease or limit the number of trading permits following the restructuring transaction. The ability to decrease or

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limit the number of trading permits is currently subject to a statutory requirement that the CBOE make available a minimum of 1025 total permits. Furthermore, in the case of a decrease or limit in the number of permits, the CBOE will be restricted from eliminating or reducing the ability to trade one or more product(s) of a Trading Permit Holder then trading those product(s), and from eliminating or reducing the ability to act in one or more trading function(s) of a Trading Permit Holder then acting in those trading function(s), unless the CBOE is permitted to do so pursuant to a rule filing submitted to the SEC.

        •     Duration. The initial trading permits will become effective upon the closing of the restructuring transaction. The initial term of the trading permits will expire at the end of the calendar month in which the restructuring transaction is completed. The trading permits will automatically renew thereafter for successive calendar months. Please see "Renewal" below for more information on renewal or termination of the trading permits. In the future, the CBOE may issue trading permits that will be valid for longer terms, such as one, three or twelve calendar months. The CBOE may also modify the duration of trading permits depending on various considerations including demand.

        •     Pricing. The initial trading permits will be issued at a monthly rate established by the CBOE and filed with the SEC.

        Going forward, the CBOE will determine the prices of trading permits from time to time and announce those prices to the Trading Permit Holders prior to any such change in rate becoming effective and prior to the date by which a Trading Permit Holder would need to notify the CBOE that the holder desires to terminate the permit prior to its automatic renewal. Prices of trading permits may vary based on, for example, whether a person is a liquidity provider or whether a person has floor access. Additionally, the CBOE may apply a surcharge for permits providing access to certain products. Prices for trading permits, however, will be the same for all permits of the same type, regardless of whether the person holding the permit had been a member of the CBOE prior to the restructuring transaction or whether such person is a new Trading Permit Holder.

        The initial permit fees that CBOE currently plans to assess are $          per month for market maker and floor broker permits, $          per month for electronic access permits, and no permit fee for CBSX permits. CBOE currently plans to discount these permit fees by 20% through the end of 2010. CBOE currently anticipates initially charging $          per month for the additional bandwidth packets made available to market maker permit holders and also discounting that fee by 20% through the end of 2010. Additionally, as further described below with respect to "tier appointments," CBOE currently intends to initially assess a $          per month surcharge to market makers that trade S&P 500 Index (SPX) options.

        An organization holding a trading permit in its name will be responsible for paying all fees and charges for that trading permit. An individual holding a trading permit in his or her name will be responsible for paying all fees and charges for that trading permit.

        •     Renewal. Prior to the expiration of a trading permit, the Trading Permit Holder may notify the CBOE that the holder is terminating the trading permit or may file an application with the CBOE to change the trading permit to a different type of trading permit. If the Trading Permit Holder does not take either of these actions, the holder's trading permit will be automatically renewed for the same period of time as the expiring permit. In renewing trading permits, the CBOE may issue one or more trading permits that represent the same or more trading rights as the expiring permit.

        Eligible Holders.     Any individual or organization wishing to obtain a trading permit following the restructuring transaction will be subject to applicable regulatory requirements under the CBOE Rules.

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Permits will be issued to organizations and individuals approved by the CBOE to hold a trading permit ("qualified persons").

        Inactive Nominees.     The CBOE will continue the status of inactive nominees so as to allow firms to have nominees who can rotate on and off permits. All inactive nominees registered as such in the CBOE Membership System on the day prior to the restructuring transaction will have their inactive status continued automatically (assuming their affiliated firm receives a trading permit), unless the inactive nominee or their affiliated firm provides the CBOE with prior written notice of termination of the inactive nominee status effective on or prior to the restructuring transaction. Immediately following the restructuring transaction, inactive nominees will continue to be assessed fees to maintain their status, generally equivalent to those being assessed immediately prior to restructuring transaction. The CBOE may determine in the future to increase, decrease, waive or eliminate the fees assessed with respect to inactive nominees. Any such determination will be communicated to the Trading Permit Holders.

        Access to Related Exchanges.     The trading permits issued by the CBOE will also provide the Trading Permit Holder with trading access to OneChicago, LLC (OneChicago). However, trading access to CBOE Futures Exchange (CFE) and "C2", the proposed second options exchange to be wholly owned by CBOE Holdings, Inc., will be provided through separate trading permits issued by CFE and C2, respectively. The trading permits issued by CBOE will not provide access to CFE and C2.

        Ability to Transfer or Assign.     Trading permits will only be issued by the CBOE and cannot be leased or transferred to any person under any circumstances, except as follows: a firm may change the designation of the nominee in respect of each trading permit it holds in a form and manner prescribed by the CBOE. In addition, a Trading Permit Holder may, with the prior written consent of the CBOE, transfer a trading permit to a firm that is or is qualified to become a Trading Permit Holder (i) which is an affiliate or (ii) which continues substantially the same business of that Trading Permit Holder without regard to the form of the transaction used to achieve such continuation, for example, a merger, sale of substantially all assets, reincorporation, reorganization or the like.

        Additional Issuances.     From time to time, the CBOE in its discretion may determine to make available additional permits of one or more types. In connection with such an issuance, a qualified person and any affiliated qualified person are eligible to receive no more than the greater of (i) 10 of the trading permits in that specific issuance or (ii) 20% of total number of any specific issuance of trading permits. This limit, however, would not apply in the event the issuance number of the trading permits exceeds the demand for the trading permits. In the event the demand for trading permits exceeds the issuance number, trading permits will be made available through a random lottery process or on a first-come, first-served basis.

        Appointment Process.     Following the restructuring transaction, the CBOE intends to keep the existing appointment process (e.g., class quoting and appointment costs) specified in the CBOE Rules. The CBOE also will have the authority to issue various types of trading permits that will allow Trading Permit Holders to: (i) act in one or more of the trading functions permitted under the CBOE's Rules (e.g., floor broker, market maker, etc.); and (ii) subject to the appointment process (e.g., class quoting limits and appointment costs) in the Rules, to trade one or more of the securities permitted to be traded on the CBOE. Under this provision, for example, the CBOE would have the authority to issue trading permits that will allow applicants to act as specific types of liquidity providers in particular options classes.

        Tier Appointments.     CBOE may also create a new type of appointment called a "tier appointment." A "tier appointment" is an appointment to trade one or more options classes that must be held by a market maker to be eligible to trade the options class or options classes subject to that appointment. CBOE currently plans to have one initial type of tier appointment for market makers that

60

trade SPX options. The application and issuance processes for tier appointments will be in accordance with, and subject to the same terms and conditions as, the application and issuance processes for trading permits as described above. A tier appointment will be for the same term as the trading permit with which the tier appointment is associated. Termination, change, renewal, and transfer of tier appointments, and the authority of the CBOE to limit, reduce, or increase tier appointments, will also be in accordance with, and subject to the same terms and conditions as, the processes for trading permits as described above. Tier appointments will be in addition to the current appointment cost process under the CBOE Rules, which will remain unchanged in connection with the restructuring transaction. As with trading permits, the CBOE will from time to time determine and announce to the members the price of each tier appointment, and the prices may vary by tier appointment.

        Other Rules.     The other CBOE Rules applicable to trading permits will be substantially similar to those in place today with respect to memberships.

        Trading Access Rules Subject to SEC Approval.     Before the CBOE Rules related to access go into effect, they must be approved by the SEC. Accordingly, the CBOE Rules related to access as finally adopted may differ from those described above. The CBOE's program for providing trading access following the restructuring transaction will be in accordance with the CBOE's Rules as in effect at that time. Before any changes to the CBOE Rules related to access go into effect, they must first be published for comment and then approved by the SEC.

Amendments to the CBOE Certificate of Incorporation, Constitution and Bylaws

        As part of the restructuring transaction, the bylaws and certificate of incorporation for the CBOE will be amended and restated to reflect the new holding company structure, certain technical amendments required as a result of converting from a membership organization to a stock corporation and to change the capital structure and governing structure contained in such documents. The amended and restated bylaws of the CBOE will replace the CBOE's current Constitution, and following the restructuring transaction, the CBOE's amended and restated bylaws will no longer include the CBOE Rules. Please review carefully all the terms and conditions of the amended and restated bylaws and certificate of incorporation of not only the CBOE, but also CBOE Holdings. We have included the form of amended and restated certificate of incorporation for CBOE Holdings and form of amended and restated bylaws for CBOE Holdings in this proxy statement and prospectus as Annex C and D, respectively. The form of certificate of incorporation of the CBOE and form of amended and restated bylaws of the CBOE are also included in this proxy statement and prospectus as Annex E and F, respectively.

        Some of the more significant provisions of the CBOE and CBOE Holdings certificates of incorporation and bylaws are summarized below. For additional information on capital stock and corporate governance of the CBOE and CBOE Holdings, see "Comparison of Rights Prior to and After the Restructuring Transaction" on page 189.

        Capital Stock.     Pursuant to its certificate of incorporation, CBOE Holdings is authorized to issue (i) 325,000,000 shares of unrestricted common stock, par value $0.01 per share, (ii) 74,400,000 shares of Class A common stock, par value $0.01 as per share, (iii) 45,366,690 shares of Class A-1 common stock, $0.01 par value per share, (iv) 45,366,690 shares of Class A-2 common stock, $0.01 par value per share, (v) 16,333,380 shares of Class B common stock, $0.01 par value per share, and (vi) 20,000,000 shares of preferred stock. After the restructuring transaction, the CBOE will be authorized to issue 1,000 shares of common stock, par value $0.01 per share. All CBOE shares will be held by CBOE Holdings.

        Voting Rights.     After the restructuring transaction, you will hold ownership interests in CBOE Holdings and not the CBOE. These new ownership interests will entitle you to vote on matters pertaining to CBOE Holdings. You will no longer vote on matters at the CBOE. CBOE Holdings, as

61

the sole stockholder of the CBOE, will have the right to vote generally with respect to CBOE matters, including for the election of directors and on other matters as required by the bylaws, certificate of incorporation and the law of the State of Delaware. As a voting stockholder of CBOE Holdings, you will be entitled to vote, along with all other holders of CBOE Holdings voting common stock generally, with respect to CBOE Holdings matters, including for the election of directors and on other matters required by the bylaws, certificate of incorporation or the laws of the State of Delaware.

        Voting Limitations.     No person, together with its related persons, may vote or cause to vote more than 20% of the voting power of CBOE Holdings without the prior approval of the board of directors of CBOE Holdings and, in certain circumstances, the SEC. This limitation is described in more detail below at "Description of CBOE Holdings Capital Stock" on page 174.

        Ownership Limitations.     No person, together with its related persons, may directly or indirectly beneficially own more than 20% of the outstanding shares of common stock of CBOE Holdings without the prior approval of the board of directors of CBOE Holdings and, in certain circumstances, the SEC. For additional information about this limitation and additional information about the capital stock of CBOE Holdings, see "Description of CBOE Holdings Capital Stock" on page 174.

        Board of Directors.     There will be a separate board of directors for each of the CBOE and CBOE Holdings. Because there is currently an off-floor director vacancy on the CBOE board that is expected to remain as a vacancy until the effective time of the restructuring transaction, the CBOE board currently has 22 directors. After the restructuring transaction, the CBOE board will be reduced to 22 members and will consist of the same 22 directors who are serving on the board immediately prior to the restructuring transaction. The CBOE Holdings board will have the same 22 directors. At all times, the CBOE Holdings board will consist of the CBOE Holdings' chief executive officer and 21 other directors, no less than two-thirds of whom will at all times meet the independence requirements of CBOE Holdings and those established by the New York Stock Exchange and NASDAQ Stock Market. The CBOE board will consist of the CBOE's chief executive officer, as well as non-industry directors making up at least a majority of the board and industry directors making up at least 30% of the board, as each of those director classifications is defined in the applicable bylaws and certificate of incorporation. Failure of a director to maintain the categorical requirements of either a non-industry or an industry director may result in the director's removal from the board. Directors of each of the CBOE and CBOE Holdings will be elected by a plurality of votes. The CBOE board will no longer be a classified board with staggered terms of office. Rather, each director will serve for one year or until his or her successor is elected and qualified. Directors of CBOE Holdings will also serve for one year or until a successor is elected and qualified. There is no limit on the number of terms a director may serve on either board.

        Nomination of Directors.     After the restructuring transaction, the Nominating and Governance Committee of the CBOE will be comprised solely of board members and will nominate all directors for election at the CBOE. It is currently anticipated that the members of the Nominating and Governance Committee of the CBOE will be the same as the members of the Nominating and Governance Committee of CBOE Holdings. At the CBOE, however, the Nominating and Governance Committee will have an Industry-Director Subcommittee, which will consist of all of the industry directors serving on the Nominating and Governance Committee. The Industry-Director Subcommittee shall select industry directors that equal at least 20% of the directors serving on the board of the CBOE. For a discussion of the nomination procedures at each of CBOE Holdings and the CBOE, please see "Directors and Management of the CBOE And CBOE Holdings After the Restructuring Transaction—Committees of the CBOE Holdings Board of Directors—Nominating and Governance Committee" on page 143.

        Exercise Right.     As part of the restructuring transaction, the certificate of incorporation of the CBOE will be amended to remove Article Fifth(b) as it would no longer be applicable to a

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demutualized CBOE. In any event, as a result of the CME/CBOT Transaction and the approval by the SEC of the Eligibility Rule Filing and the Delaware Court's approval of the Settlement Agreement becoming final, there no longer are members of the CBOT who qualify to become a member of the CBOE under Article Fifth(b). Following the restructuring transaction, there will no longer be any reference in the CBOE certificate of incorporation to the Exercise Right described in the former certificate of incorporation of the CBOE.

Amendments to the CBOE Rules

        In addition to the changes to the CBOE's Constitution, certificate of incorporation and bylaws, as part of the restructuring transaction, the CBOE's Rules will be amended:

•

to reflect that access to the CBOE's trading facilities will be made available through the issuance of trading permits as described in the section "—Trading Permits" above and to clarify the CBOE's regulatory authority over trading permits and trading permit holders;



•

to establish a new type of appointment called a "tier appointment" as described in the section "—Trading Permits" above;



•

to make technical, conforming changes to reflect the restructuring transaction and the issuance of trading permits (for example, to replace the term "member" throughout with the term "trading permit holder" to reflect that ownership will be separated from trading access following the restructuring transaction, and to delete the reference to the term "lessor" and the related language in the Rules because the concept of leasing memberships will not exist after the restructuring of the CBOE);



•

to modify the procedures for the appointment of members to CBOE committees that are not comprised solely of members of the CBOE's board as well as the process for filing vacancies on such committees;



•

to clarify the ability of the board of CBOE to review, modify, suspend or overrule any action (or inaction) of CBOE committees, officers, representatives and designees taken (or not taken) pursuant to the CBOE Rules; and



•

to confirm that the former process for application to become a member will apply going forward to the process to become a trading permit holder and that existing rules with respect to qualifications will continue with respect to permit holders (although many of the applicable rules will be revised to reflect the issuance of trading permits).

        The amendments to the Rules were previously submitted to the members of the CBOE in an Exchange Bulletin issued by the CBOE on August 29, 2008. In addition, to effect the majority of the amendments to the Rules described above and through this proxy statement and prospectus (as well as other immaterial amendments), the CBOE filed these proposed rule changes with the SEC on August 21, 2008 (Rule Filing No. SR-CBOE-2008-88). A copy of the rule filing is available on the CBOE's website at www.cboe.org/legal/submittedSECfilings.aspx. The notice of the proposed Rules was published in the Federal Register on August 26, 2008. A copy of the published notice may be obtained at the SEC's website at www.sec.gov/rules/sro/cboe/2008/34-58425.pdf. These changes to our Rules, which are subject to further change, will take effect at the time of the amendment to the certificate of incorporation of the CBOE as a result of the Merger.

         We urge you to review carefully the amended Rules and the published notice with respect to such Rules before voting on the proposed restructuring transaction.

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Exercise Right Settlement Agreement

        On August 23, 2006, the Delaware Action was filed. In that action, the CBOE and its directors were sued in the Court of Chancery of the State of Delaware, by the CBOT, CBOT Holdings Inc. and two members of the CBOT who purported to represent a class of individuals who claimed they were, or had the right to become, members of the CBOE pursuant to the Exercise Right. The plaintiffs sought a judicial declaration that each Exercise Member Claimant was entitled to receive the same consideration in any proposed restructuring transaction involving the CBOE as a CBOE Seat owner, and the plaintiffs also sought an injunction to bar the CBOE and the CBOE's directors from issuing any stock to CBOE Seat owners as part of a proposed restructuring transaction, unless each Exercise Member Claimant received the same stock and other consideration as a CBOE Seat owner. For more information regarding this litigation, please see "Business—Legal Proceedings—Litigation with Respect to the Restructuring Transaction" on page 121.

        On August 20, 2008, the CBOE entered into the Settlement Agreement with the plaintiffs pursuant to which the plaintiffs agreed to dismiss the Delaware Action, with prejudice, in exchange for the specified settlement consideration. The following summary addresses the material terms of the Settlement Agreement, but does not describe every term of the Settlement Agreement. You are encouraged to read the entire document, a copy of which is filed as Exhibit 4.4 to the Registration Statement on Form S-4 of which this proxy statement and prospectus is a part.

        The Participating Group A Settlement Class Members and the Participating Group B Settlement Class Members will not receive any consideration in the restructuring transaction or in the Merger effecting the restructuring transaction. As such, the disclosures contained in this proxy statement and prospectus, including those related to the restructuring transaction and the federal income tax consequences of the restructuring transaction, are not intended for, and should not be relied upon by, the Participating Group A Settlement Class Members and the Participating Group B Settlement Class Members.

        Settlement Class Members.     The approved Settlement Agreement includes a non-opt out settlement class, which means that everyone in the settlement class definition is bound by the Settlement Agreement and does not have the right to pursue separate claims against the CBOE. The settlement class consists of two groups:

•

The first group (Group A) consists of all persons who, prior to August 22, 2008, simultaneously beneficially owned or possessed at least one CBOT B-1 membership, at least one Exercise Right Privilege and at least 27,338 shares of CBOT stock or (after the closing of the CME/CBOT Transaction) 10,251.75 shares of CME Group stock. An Exercise Right Privilege is the privilege, whether or not that privilege or right had been unbundled from a CBOT B-1 Membership, that when held together with a CBOT B-1 Membership and the requisite shares of CBOT Common Stock qualified a person as holding an Exercise Right. In order to receive a share of the settlement consideration paid to Group A, the members of Group A also must (1) have owned the package of three interests as of 5:00 p.m. (central time) on October 14, 2008 and continued to own that package until October 31, 2008 and (2) have met certain other eligibility and procedural conditions contained in the Settlement Agreement. We sometimes refer to members of Group A who met the conditions for receiving settlement consideration as Participating Group A Settlement Class Members, and we sometimes refer to the package of interests described in this bullet as a Group A Package.



•

The second group (Group B) consists of all persons who owned an Exercise Right Privilege as of 5:00 p.m. (central time) on October 14, 2008 (excluding Exercise Right Privileges that were used as components of Group A Packages) and their transferees and assigns. In order to receive a payment from the Group B settlement consideration, members of Group B must have met certain other eligibility and procedural conditions contained in the Settlement Agreement. We

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sometime refer to members of Group B who met the conditions for receiving settlement consideration as Participating Group B Settlement Class Members.

        Financial Terms of Settlement Agreement.     Settlement class members will share the following settlement consideration:

•

Participating Group A Settlement Class Members will share in an equity pool which will consist of 16,333,380 shares of Class B common stock of CBOE Holdings.



•

The rights associated with this common stock must be identical to the rights of the stock issued to CBOE Seat owners, except that the stock to be issued to the Participating Group A Settlement Class Members will be non-voting (except under limited circumstances) unless and until there is an initial public offering of the stock of the restructured company, at which point the stock issued to Participating Group A Settlement Class Members will convert into the same type of stock issued to the CBOE Seat owners.



•

Each Participating Group A Settlement Class Member will receive from the equity pool 18,774 shares of Class B common stock for each Group A Package it owns, representing a pro rata share of the total equity pool based on the number of Group A Packages that were approved by the Delaware Court.



•

The Participating Group A Settlement Class Members will have a right to receive the Class B common stock of CBOE Holdings immediately following the effectiveness of the Merger. As such, CBOE Holdings intends to arrange for its transfer agent to issue the Class B common stock of CBOE Holdings to the Participating Group A Settlement Class Members pursuant to the Settlement Agreement concurrently with the issuance by the transfer agent of the Class A common stock of CBOE Holdings to the CBOE Seat owners in the restructuring transaction.



•

Participating Group A and Group B Settlement Class Members will share in a cash pool equal to $300,000,000.



•

For each Group B unit approved by the Court, that unit will receive $250,000 from the cash pool.



•

Each Participating Group A Settlement Class Member will receive $235,327.58 for each Group A Package approved by the Delaware Court.



•

CBOE is required to distribute the cash pool under the Settlement Agreement upon the completion of any restructuring transaction or any other transaction in which the CBOE Seats are converted into cash or other securities. If the restructuring transaction described in this proxy statement and prospectus is not consummated within one year after the approval of the Settlement Agreement by the Delaware Court became final, the CBOE will be required to distribute the cash pool, regardless of whether any restructuring of the CBOE has occurred or any other transaction has been consummated. As such, if the Agreement and Plan of Merger proposed in this proxy statement and prospectus is approved by the CBOE members, the CBOE will arrange for the distribution of the funds in the cash pool to the Participating Group A Settlement Class Members and the Participating Group B Settlement Class Members immediately following the consummation of the Merger.



•

Certain Participating Group A Settlement Class Members who were also CBOE Temporary Members will receive a payment from CBOE, separate from the cash pool, equal to the amount each of those class members paid in access fees as CBOE Temporary Members from July 11, 2007 to May 31, 2008. The total amount of the CBOE's liability for these payments is $828,029. CBOE Temporary Members are those CBOE members who, prior to the CME/CBOT

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Transaction had used their Exercise Right to become members at the CBOE, were in good standing with the CBOE at the time of the CME/CBOT Transaction and were allowed to temporarily retain their CBOE membership status pursuant to the Interim Access Interpretation and the Continued Membership Interpretation.

•

Certain of the Participating Group A Settlement Class Members who are entitled to the foregoing payment also will receive a payment, separate from the cash pool, equal to the access fees which that Group A class member paid to the CBOE as a CBOE Temporary Member from June 1, 2008 until the date that the CBOE completes a restructuring transaction. We sometimes refer to these payments and the payments indentified in the prior bullet as the "fee-based payments." As such, if the Agreement and Plan of Merger proposed in this proxy statement and prospectus is approved by the CBOE members and the CBOE consummates the Merger, the amount of this payment obligation will cease accruing as of the Merger.



•

Prior to any CBOE restructuring transaction, the CBOE will not pay dividends or make other payments to CBOE Seat owners as a group or repurchase membership interests from CBOE Seat owners. If CBOE Seat owners receive additional consideration as a group (other than the stock they would receive if the restructuring transaction described in this proxy statement and prospectus were completed), or if any other rights are granted or retained by CBOE Seat owners as a group, then the same type of consideration will be put in a pool for Participating Group A Settlement Class Members in an amount that would equal to 18% of the total additional consideration paid or granted to CBOE Seat owners and the Participating Group A Settlement Class Members.



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The CBOE will offer any Participating Group A Settlement Class Member who was also a CBOE Temporary Member immediately prior to any CBOE restructuring transaction, including the restructuring transaction described in this proxy statement and prospectus, an opportunity to obtain a trading permit in the CBOE on the same terms and conditions as such trading permits are offered to CBOE Seat owners.



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The CBOE agreed that in setting the initial rates to be charged for trading permits following any CBOE restructuring transaction, the CBOE's Board of Directors will set those rates in good faith and at a level it believes will be in the best interest of the CBOE as a whole and all of its stockholders following any restructuring transaction.

        Pursuant to the Settlement Agreement, the Court of Chancery of the State of Delaware's order of approval and final judgment contains:

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a finding that there no longer are any persons eligible to become members of the CBOE pursuant to the Exercise Right,



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a finding that the Exercise Right does not provide any person the right to vote, trade or participate in the CBOE's restructuring transaction, and



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a release from any claims by the plaintiffs and class members related to the Exercise Right, and an injunction against those parties from bringing another action asserting claims related to the Exercise Right.

        Following the December 2, 2009 order entered by the Delaware Supreme Court dismissing the appeals from the Court of Chancery's order of approval and final judgment approving the Settlement Agreement, the order of approval and final judgment is no longer subject to appeal.

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Shares of CBOE Holdings reserved for issuance to CBOE and CBOE Holdings Directors and Management

        The board of directors of the CBOE has adopted the Long-Term Incentive Plan, pursuant to which the directors of the CBOE and CBOE Holdings, as well as management and other employees of the CBOE and CBOE Holdings, may be granted equity compensation as determined by the board of directors of CBOE Holdings from time to time. A total of 2,489,039 shares of unrestricted common stock have been reserved for issuance under the Long-Term Incentive Plan. Approximately 2,240,552 shares of unrestricted common stock will be issued to the directors of CBOE and employees of CBOE effective immediately following the effectiveness of the restructuring transaction. The shares will be issued as restricted stock grants, as defined in the Long-Term Incentive Plan, and all such shares will be subject to vesting, as more fully described under "Directors and Management of CBOE and CBOE Holdings After the Restructuring Transaction—Executive Compensation" below. There will be 248,487 shares of unrestricted common stock remaining for future issuance under the Long-Term Incentive Plan.