FORWARD-LOOKING STATEMENTS

        We make forward-looking statements under the "Summary," "Risk Factors," "Information About the CBOE," "Information About CBOE Holdings," "CBOE Management's Discussion and Analysis of Financial Condition and Results of Operations," and in other sections of this document, as well as in other documents and sources of information that may be made a part of this document by appearing in other documents that we file with the SEC and incorporated by reference into this document. These statements may include statements regarding the period following completion of the restructuring transaction. In some cases, you can identify these statements by forward-looking words such as "may," "might," "should," "expect," "plan," "anticipate," "believe," "estimate," "predict," "potential" or "continue," and the negative of these terms and other comparable terminology. These forward-looking statements, which are subject to known and unknown risks, uncertainties and assumptions about us, may include projections of our future financial performance based on our growth strategies and anticipated trends in our business. These statements are only predictions based on our current expectations and projections about future events. There are important factors that could cause our actual results, level of activity, performance or achievements to differ materially from the results, level of activity, performance or achievements expressed or implied by the forward-looking statements. In particular, you should consider the numerous risks and uncertainties described under "Risk Factors."

        While we believe we have identified material risks, these risks and uncertainties are not exhaustive. Other sections of this document describe additional factors that could adversely impact our business and financial performance. Moreover, we operate in a very competitive and rapidly changing environment. New risks and uncertainties emerge from time to time, and it is not possible to predict all risks and uncertainties, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements.

        Although we believe the expectations reflected in the forward-looking statements are reasonable, we cannot guarantee future results, level of activity, performance or achievements. Moreover, neither we nor any other person assumes responsibility for the accuracy or completeness of any of these forward-looking statements. You should not rely upon forward-looking statements as predictions of future events. We are under no duty to update any of these forward-looking statements after the date of this document to conform our prior statements to actual results or revised expectations, and we do not intend to do so.

        Forward-looking statements include, but are not limited to, statements about:

•

our business' possible or assumed future results of operations and operating cash flows;



•

our business' strategies and investment policies;



•

our business' financing plans and the availability of capital;



•

our business' competitive position;



•

potential growth opportunities available to our business;



•

the risks associated with potential acquisitions or alliances by us;



•

the recruitment and retention of our officers and employees;



•

our expected levels of compensation;



•

our business' potential operating performance, achievements, productivity improvements, efficiency and cost reduction efforts;



•

the likelihood of success and impact of litigation;

27

•

our protection or enforcement of our intellectual property rights;



•

our expectation with respect to securities, options and future markets and general economic conditions;



•

our ability to keep up with rapid technological change;



•

the effects of competition on our business; and



•

the impact of future legislation and regulatory changes on our business.

        We caution you not to place undue reliance on the forward-looking statements, which speak only as of the date of this document in the case of forward-looking statements contained in this document, or the dates of the documents incorporated by reference into this document in the case of forward-looking statements made in those incorporated documents.

        WE EXPRESSLY QUALIFY IN THEIR ENTIRETY ALL FORWARD-LOOKING STATEMENTS ATTRIBUTABLE TO THE CBOE OR CBOE HOLDINGS OR ANY PERSON ACTING ON OUR BEHALF BY THE CAUTIONARY STATEMENTS CONTAINED OR REFERRED TO IN THIS SECTION.

28

        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                        , 2009, 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 has the right to vote. As of the date of this document, there are 1,042 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 1,042 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. As a result, if a CBOE member 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 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 1.34% 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 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, 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 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

29

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 ballot 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 ballots in-person on the trading floor beginning            ,            , 2009. 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 ballot along with your proxy to cast your ballot on your behalf 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 ballot, proxy card and a postage paid return envelope. You may submit your ballot (along with your proxy to cast your ballot on your behalf) by mail in the postage paid envelope, by fax or hand delivery to the Office of the Secretary on the 7th floor of the Exchange, or you can submit your ballot and proxy through the Internet or by telephone. When voting by proxy, your ballot indicates how you are voting on the proposals at issue, and the proxy authorizes a designated person to place your ballot in the ballot box at the meeting and to vote on your behalf on any other matters that may properly come before the meeting.

        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            , 2009.)

•

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



•

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



•

Have your ballot ready, and then follow the simple instructions.



•

Your vote will be confirmed and cast as you directed.

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

•

Mark the ballot. 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 firm (if applicable), on the ballot. Be sure to indicate the legal name in which your membership is held.



•

Sign and date your ballot and return it in the postage-paid envelope by            , 2009.

30

•

Only ballots sealed in the appropriate envelope (unless transmitted by fax) and accompanied by a legibly executed proxy or ballots cast in person at the meeting will be counted.

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

         Members are encouraged to submit the ballot promptly in order to ensure timely receipt and an efficient election. You may verify receipt of your ballot 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.

        Ballots, along with a duly executed proxy authorizing the persons designated herein to cast such ballot at the special meeting, must be received prior to     p.m., Central Time, on            , 2009 in order to be counted.

        All ballots (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 ballots. If no vote is indicated on a ballot that has been delivered with a properly executed proxy card, the CBOE membership(s) represented by the ballot and 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 ballot and properly executed proxy card and have indicated that you have abstained from voting on a proposal, your CBOE memberships represented by the ballot and 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 ballot or voting instruction card to indicate how to vote your CBOE membership.

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

•

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;



•

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



•

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 ballot or granted 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 change any previously delivered ballot or to revoke any previously granted proxy using the methods described above.

        Returning your completed ballot and proxy will not prevent you from changing your vote or revoking your proxy and voting in person at the special meeting of Members. Please note, however, that if you submit your ballot and 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 deliver your ballot with respect to the proposal to be brought at the special meeting.

Confidential Voting

        It is the CBOE's policy that all ballots and voting tabulations that identify the CBOE members be kept confidential. The CBOE intends to engage a third-party firm to serve as inspector of election and

31

count the ballots. The CBOE Election Committee will oversee the third-party firm selected to count the ballots.

Solicitation of Ballots and Proxies

        The CBOE board of directors is making the solicitation of ballots and proxies. The CBOE will pay the expenses incurred in connection with the printing and mailing of this document. To assist in the solicitation of ballots and proxies, the CBOE has retained            for a fee not to exceed $                  plus reimbursement of out-of-pocket expenses. Solicitation of ballots and 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 solicitation.

32

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 171.

General

        The restructuring transaction will be completed through the following steps:

•

The creation of CBOE Holdings, Inc. as a new Delaware stock, for-profit subsidiary corporation, and CBOE Merger Sub, Inc. as a second-tier, Delaware stock, for-profit corporation.



•

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."



•

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 the right to receive CBOE Holdings common stock and the CBOE Holdings common stock 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 other than CBOE Stock Exchange, LLC (CBOE Futures Exchange, LLC, Chicago Options Exchange Building Corporation, CBOE, LLC, CBOE II, 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 50% interest.

        As part of the restructuring transaction, each CBOE Seat existing as of the date of the restructuring transaction will be converted into the right to receive              shares of Class A CBOE Holdings common stock. In addition, Participating Group A Settlement Class Members will be issued, immediately following the Merger, Class B common stock of CBOE Holdings as required by the Settlement Agreement. As a result, the owners of the CBOE Seats outstanding immediately prior to the restructuring transaction will own 100% of the Class A common stock, and the Participating Group A Settlement Class Members will be issued 100% of the Class B common stock, which in the aggregate will equal approximately 21.9% of the number of shares of the Class A common stock issued to the CBOE Seat Owners in the restructuring transaction. As a result, the Class A common stock issued in the restructuring transaction and the Class B common stock issued pursuant to the Settlement Agreement will represent approximately 82% and 18%, respectively, of the combined total common stock issued to the Seat Owners in the restructuring transaction and the Participating Group A Settlement Class Members pursuant to the Settlement Agreement.

        The 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, except that Class B common stock issued in connection with the

33

Settlement Agreement will have no voting rights or privileges except as described in "Description of CBOE Holdings Capital Stock—Common Stock" on page 146. 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 160 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 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 44.

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, 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 Business Model Task Force consisted of four independent directors and three member directors and was chaired by James Boris, an independent director. Although the Business Model Task Force often met in executive sessions at which only members of the Task Force were present, in conducting its review and analysis, the Task Force was assisted by the management of the CBOE and by Goldman, Sachs & Co., an investment banking firm hired by the Task Force for this purpose. 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 Business Model 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.

34

        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 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 Exchange'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 Business Model 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

35

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 for such a restructuring.

        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 its financial advisors, Goldman Sachs, its legal counsel, Schiff Hardin, special legal counsel, Sullivan & Cromwell, 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. In one case, these exploratory discussion lead to an extensive due diligence process. 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

36

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 CBOT, in concert with others, initiated a purported class action lawsuit in Delaware against the CBOE and its directors regarding the demutualization of the CBOE. The CBOT lawsuit 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 to have the Delaware Chancery Court issue a 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 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, the Chicago Mercantile Exchange Holdings, Inc., or CME Holdings, and CBOT Holdings Inc. announced that CME Holdings would acquire the CBOT. 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 acquisition transaction on the eligibility of CBOT members to become and remain members of the CBOE pursuant to the Exercise Right provided for in paragraph (b) of Article Fifth, or Article Fifth(b), of the CBOE's certificate of incorporation.

        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 CBOE 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 this determination and (2) authorization for the CBOE, upon completion of the CME/CBOT Transaction, to grant temporary access to former Exercise Member Claimants 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 Exercise Member Claimants. 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 CME Holdings' acquisition on the Exercise Right and based on the board's understanding that the acquisition would likely close prior to the demutualization of the CBOE, the Special Committee would defer further deliberations until such

37

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 against the CBOE filed an amended complaint that challenged the interpretation of Article Fifth(b) that the CBOE had filed with the U.S. Securities and Exchange Commission on December 12, 2006. On January 11, 2007, plaintiffs submitted 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 Commission. On January 16, 2007, CBOE and the director defendants moved to dismiss the amended complaint to the extent it challenged CBOE's interpretation, on the ground that the U.S. Securities and Exchange Commission's jurisdiction to consider such interpretations of Article Fifth(b) preempts any state law challenge to that interpretation. In this motion, defendants further moved to stay consideration of plaintiffs' claims regarding the consideration to which Exercise Member Claimants otherwise would be entitled until it was known whether the CME Holdings acquisition of CBOT would close before CBOE's restructuring.

        On January 25, 2007, at a regular scheduled meeting of the CBOE board of directors, management made a presentation describing the restructuring transaction and 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 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 shareholders approved the CME merger proposal. 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 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 membership status of those persons who temporarily retained their CBOE membership status pursuant to the interim access interpretation would continue 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.

38

        On January 15, 2008, the SEC approved the CBOE rule filing 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 management and class representative engaged in periodic settlement discussions. On June 2, 2008, two days before the Delaware Court was to hear argument on motions for summary judgment, the parties entered into a written agreement in principle to settle both the Delaware litigation and the appeal of 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 agreement. On August 20, 2008, the parties entered into a definitive Stipulation of Settlement 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 membership approved the Settlement Agreement.

        On December 16, 2008, the Delaware Court conducted a lengthy hearing to consider whether to approve the settlement of the litigation and to consider the objections to the proposed settlement. At the conclusion of the hearing, the Court indicated that it would issue a comprehensive written opinion, but it did not indicate when that decision would be forthcoming.

        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 a final order approving the Settlement Agreement, resolving all open issues about the settlement and dismissing the Delaware litigation. The order is subject to any appeals that may be filed by August 28, 2009. No appeals had been filed as of the date this registration statement was filed.

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 27.

39

        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 and creating a framework for a possible future public offering of CBOE Holdings common stock.

        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 shareholder 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 "The Restructuring Transaction—Trading Permits" on page 44 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 shareholders 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 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 reduction in the size of the board and a reduction in the number of member committees;



•

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:

•

facilitate CBOE Holdings' engaging 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;

40

•

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 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 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."

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:

•

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.

What You Will Receive in the Restructuring Transaction

        CBOE Holdings, Inc. Common Stock.     In the restructuring transaction, each CBOE Seat existing on the date of the restructuring transaction will be converted into the right to receive             shares of Class A common stock of CBOE Holdings. In addition, Participating Group A Settlement Class Members will be issued, immediately following the Merger and as required by the Settlement Agreement,             shares of Class B common stock of CBOE Holdings.

        If CBOE Holdings completes a 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, effective upon completion of such public offering. 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

41

certain transfer restrictions that will continue following the closing of a public offering for different durations. For a description of these transfer restrictions, please see below. In addition, effective upon the expiration of the lock-up period associated with the shares of Class A-1 and Class A-2 common stock, such shares shall automatically convert into shares of unrestricted common stock of CBOE Holdings, and such shares shall be freely tradable.

        Transfer of CBOE Holdings Common Stock Following the Restructuring Transaction.     Following the restructuring transaction and unless and until a public offering by CBOE Holdings of its common stock has been completed, pursuant to the certificate of incorporation of CBOE Holdings, transfers of the Class A and Class B common stock of CBOE Holdings may only take place through the agent of CBOE Holdings that has been designated by CBOE Holdings to manage such transfers and through the broker or market designated by CBOE Holdings as the sole broker or market for such transfers. The broker designated by CBOE Holdings will maintain a record of the prices bid and offered by sellers and buyers and the time such bids and offers are submitted to the broker. When a bid and offer match, the broker will consummate the transaction and inform the parties. It is intended that this process will function much like the existing process for the sale and transfer of CBOE Seats.

        In addition, in the event the CBOE Holdings board of directors determines to proceed with a future public offering, the board may institute lock-up restrictions with respect to the Class A and Class B common stock by issuing a press release to the effect that such transfer restrictions will commence on a date no earlier than 10 calendar days following the date of such announcement. These transfer restrictions are sometimes referred to as the "Interim Transfer Restrictions." The Class A and Class B common stock shall remain subject to these Interim Transfer Restrictions until such shares are converted into shares of Class A-1 and A-2 common stock at the time of the closing of any such public offering. At that time, the shares of Class A-1 and A-2 common stock will be issued subject to similar transfer restrictions. During this lock-up period, shares of Class A common stock and Class B common stock of CBOE Holdings 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.

        Transfer Restrictions on CBOE Holdings Common Stock Following a Public Offering.     In the event CBOE Holdings engages in a public offering of its common stock in the future, the shares of Class A and Class B common stock automatically shall convert, effective at the time of the closing of such public offering, into shares of Class A-1 and Class A-2 common stock and upon issuance 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 any such public offering. During any applicable lock-up period, shares of the affected series of CBOE Holdings Class A or Class B 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. Subject to possible extension in the event of an organized sale, as set more fully in this proxy statement and prospectus, upon the expiration of the applicable lock-up period with respect to the common stock, the shares of the common stock then scheduled to expire would automatically convert to unrestricted common stock that would be freely transferable.

        In addition to the restrictions described above, all shares of Class A, Class B, 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.

42

Who Will Receive the Restructuring Consideration

        The CBOE Holdings Class A common stock issued in the restructuring transaction will be issued to the owner of a CBOE Seat. Therefore, if you are currently a member who owns a CBOE Seat, you will receive the CBOE Holdings Class A common stock issued in the restructuring transaction in exchange for your CBOE Seat. 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 CME/CBOT Transaction and the approval by the SEC of the eligibility rule filing, and upon final approval of the Settlement Agreement (including any appeals of that approval), there no longer will be members of the CBOT who qualify to become or remain a member of the CBOE under Article Fifth(b) of CBOE's certificate of incorporation without having to purchase a separate CBOE membership. Accordingly, at the time of the restructuring transaction, there will be no exercise memberships outstanding to be converted in 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 after the Merger effecting the restructuring transaction is complete. The Participating Group A Settlement Class Members and Participating Group B Settlement Class Members will not receive any consideration in the restructuring transaction or in the Merger effecting the restructuring transaction. For a discussion of the Settlement Agreement, please see "—Exercise Right Settlement Agreement" on page 51.

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 the right to receive shares of Class A common stock of CBOE Holdings. The CBOE Holdings Class A 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 "—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 the right to receive CBOE Holdings Class A common stock, and the

43

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 Securities Exchange Act of 1934, or 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, 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 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

44

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. All permits issued in connection with the restructuring transaction (other than the post-restructuring CBOE Stock Exchange, LLC, or CBSX, permits described below) will be of the same type and have the same trading privileges as do current CBOE memberships. Following the restructuring transaction, 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.

        •     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 July 1, 2009, there are 1,088 holders of access to the CBOE trading facilities, consisting of 930 CBOE seats, 112 temporary members, and 46 Interim Trading Permits. There are also 57 CBSX trading permit holders as of June 30, 2009. It is expected that approximately                CBOE trading permits and                CBSX trading 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 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 end 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" on page 46 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 permits will be issued at a monthly rate substantially similar to the indicative lease rate in effect for the month prior to restructuring transaction. The indicative lease

45

rate is the highest clearing firm floating monthly rate of the CBOE clearing firms that assist in facilitating at least 10% of the CBOE seat leases. The clearing firm floating monthly rate is the floating monthly rate that a clearing firm designates, in connection with the CBOE seat leases that the clearing firm assisted in facilitating, for leases that utilize that monthly rate.

        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.

        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 Rules. 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 option 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

46

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 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.     In the future, the 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. 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 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 Rules go into effect, they must be approved by the SEC. Accordingly, the Access Rules 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 Rules go into effect, they must first be published for comment and then approved by the SEC.

Organized Sales

        If CBOE Holdings completes a public offering, CBOE Holdings will have the right to conduct organized sales of the Class A-1 and A-2 common stock of CBOE Holdings issued in the restructuring transaction when the transfer restriction period applicable to the shares of Class A-1 and A-2 common

47

stock of CBOE Holdings is scheduled to expire. This right will also apply to the Class B common stock because, following any public offering, the Class B common stock will have been automatically converted to Class A-1 and A-2 common stock pursuant to CBOE Holdings' certificate of incorporation. 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 or of any other series that is subject to transfer restrictions may be sold during the applicable transfer restriction period, 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.

        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 153.

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 160.

        Capital Stock.     Pursuant to its certificate of incorporation, CBOE Holdings is authorized to issue (i)              shares of unrestricted common stock, par value $0.01 per share, (ii)              shares of Class A common stock, par value $0.01 as per share, (iii)              shares of Class A-1 common stock, $0.01 par value per share, (iv)               shares of Class A-2 common stock, $0.01 par value per share, (v)              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 unless you hold only Class B common stock, which stock does not have voting rights. You will no longer vote on matters at the CBOE. CBOE Holdings, as 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

48

bylaws, certificate of incorporation or the laws of the State of Delaware, except with respect to holders of Class B common stock, who have no voting rights or privileges except under limited circumstances more fully discussed in "Description of CBOE Holdings Capital Stock" on page 146.

        Voting Limitations.     No person, together with its related persons, may vote or cause to vote more than 10% 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. If CBOE Holdings completes a public offering of its common stock, the voting percentage that any person would be permitted to control, whether through beneficially ownership or other agreement, would increase from 10% to 20% of the total number of votes entitled to be cast on any matter. This limitation is described in more detail below at "Description Of CBOE Holdings Capital Stock" on page 146.

        Ownership Limitations.     No person, together with its related persons, may directly or indirectly beneficially own more than 10% 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. If CBOE Holdings completes a public offering of its common stock, the ownership percentage that a person would be permitted to beneficially own would increase from 10% to 20% of the total outstanding shares of CBOE Holdings common stock. 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 146.

        Board of Directors.     There will be a separate board of directors for each of the CBOE and CBOE Holdings. It is anticipated that the same individuals will be on each board immediately following the restructuring transaction. After the restructuring transaction, the CBOE board will continue to consist of the same 23 directors who are serving on the board immediately prior to the restructuring transaction. The CBOE Holdings board will have the same 23 directors. At all times, the CBOE Holdings board will consist of the CBOE Holdings' chief executive officer and 22 other directors, no less than two-thirds of whom will at all times meet the independence requirements of CBOE Holdings and those established by either the New York Stock Exchange or the 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 123.

49

        Exercise Right.     As part of the restructuring transaction, the certificate of incorporation of the CBOE will be revised to remove Article Fifth(b) as it would no longer be applicable to a 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 upon final approval of the Settlement Agreement (including any appeals of that agreement), there no longer will be members of the CBOT who qualify to become a member of the CBOE under Article Fifth(b) without having to purchase a separate CBOE membership. As a result and in connection with the other amendments being made to the CBOE's certificate of incorporation, Article Fifth(b) of the CBOE's certificate of incorporation will be deleted as part of the restructuring transaction. 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 can be obtained at the SEC's website at www.sec.gov/rules/sro/cboe/2008/34-58425.pdf. In addition, with respect to the remainder of the amendments (mostly non-substantive conforming changes), the CBOE intends to file a companion rule filing with the SEC. We will make a complete copy of that rule filing available to you as soon as it is finalized.

50

        These changes to our Rules will take effect at the time of the amendment to the certificate of incorporation of the CBOE as a result of the Merger. The form of the amended Rules of the CBOE that we currently expect to be implemented (subject to other changes to the Rules occurring after the date of this document), have been filed as an exhibit to the registration statement on Form S-4 of which this proxy statement and prospectus is a part.

         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.

Exercise Right Settlement Agreement

        On August 23, 2006, the CBOE and its directors were sued in the Court of Chancery of the State of Delaware, by the CBOT, CBOT Holdings Inc., the parent corporation of the CBOT, and two members of the CBOT who purported to represent a class of individuals who claim that they were, or had the right to become, members of the CBOE pursuant to the Exercise Right. The plaintiffs sought a judicial declaration that Exercise Member Claimants were entitled to receive the same consideration in any proposed restructuring transaction involving the CBOE as all other CBOE members, and the plaintiffs also sought an injunction to bar the CBOE and the CBOE's directors from issuing any stock to CBOE members as part of a proposed restructuring transaction, unless the Exercise Member Claimants received the same stock and other consideration as other CBOE members. For more information regarding this litigation, please see "Business—Legal Proceedings—Litigation with Respect to the Restructuring Transaction" on page 106.

        After two years of litigating issues in Delaware, the CBOE entered into a Stipulation of Settlement with the plaintiffs on August 20, 2008, pursuant to which the plaintiffs agreed to dismiss the pending action in Delaware, with prejudice, in exchange for the 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 will receive the equity portion of the settlement consideration described below only after the Merger effecting the restructuring transaction is completed. 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 Settlement Agreement calls for a non-opt out settlement class, which means that anyone in the settlement class 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 CME's acquisition of CBOT) 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 (or following the CME Transaction, shares of CME Group Common Stock) constituted the 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.

51

(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 sometime refer to members of Group A who meet these 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 those whose Exercise Right Privileges all are being 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 sometime refer to members of Group B who meet these 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 an amount of Class B common stock of CBOE Holdings equal to the product of (i) 0.21951220 times (ii) the aggregate number of shares of Class A common stock issued to owners of CBOE Seats in the restructuring transaction.



•

The rights associated with this common stock must be identical to 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 would convert into the same type of stock issued to the CBOE Seat Owners.



•

Each Participating Group A Settlement Class Member will receive for each Group A Package it owns a pro rata share of the total equity pool based on the number of Group A Packages that exist.



•

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 Exercise Right Privilege that a Participating Group B Settlement Class Member owns on October 14, 2008, that class member will receive $250,000 from the cash pool.



•

The remainder of the cash pool, after making a minor payment to one of the class representatives, will be distributed to each Participating Group A Settlement Class Member on a pro rata basis for each Group A Package the Group A class member owned compared to the total number of Group A Packages that were owned by Participating Group A Settlement Class Members on October 14, 2008.



•

CBOE is required to distribute the cash required under the Settlement Agreement upon the earlier of (i) any restructuring transaction or any other transaction in which the CBOE Seats are converted into cash or other securities. If the restructuring transaction described

52

in this proxy statement and prospectus is not consummated within one year of the final approval of the Settlement Agreement by the Delaware court, the CBOE will be required to distribute the money in 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, separate from the cash pool, equal to the amount each of those class members paid in access fees as CBOE Temporary Members from July 1, 2007 to May 31, 2008. The total amount of the CBOE's liability for these payments is capped at $2,800,000. CBOE Temporary Members are those CBOE members who, prior to the CME/CBOT 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 interpretation of Rule 3.19 of the CBOE's Rules (as filed with the SEC in Rule Filing SR-CBOE-2007-77) and in the transition rule filing (as filed with the SEC in Rule Filing SR-CBOE-2007-107).



•

Subject to SEC approval, 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. 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.



•

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.



•

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 shareholders following any restructuring transaction.



•

The CBOE agreed that it cannot sell the Exercise Right Privileges that it owns to persons attempting to become Participating Group A or Group B Settlement Class Members and that the CBOE cannot participate as a Group A or Group B class member.

53

        Pursuant to the Settlement Agreement, the plaintiffs agree that upon final approval of the Settlement Agreement:

•

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



•

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



•

the CBOE will be released from any claims by the plaintiffs and class members, all of whom will be enjoined from asserting claims against the CBOE that they have any rights with respect to the Exercise Right.

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

        The board of directors of the CBOE has adopted a 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.                          shares of unrestricted common stock have been reserved for issuance under the plan. It is currently anticipated that approximately                         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 2009 Long-Term Investment Plan.