RISK FACTORS

In addition to general investment risks and the other information contained in or incorporated by reference into this proxy statement/prospectus, including the matters addressed under the heading “Cautionary Statement Regarding Forward-Looking Statements” commencing on page 14 and the matters discussed under the caption “Risk Factors” in the Annual Reports on Forms 10-K filed by Comerica and Sterling, respectively, for the year ended December 31, 2010, as updated by other reports filed with the SEC, you should carefully consider the following risk factors in deciding how to vote on approval of the merger agreement.

Because the exchange ratio is fixed and market price of Comerica common stock will fluctuate, Sterling shareholders cannot be sure of the market value of the merger consideration they will receive.

Upon completion of the merger, each share of Sterling common stock will be converted into 0.2365 of a share of Comerica common stock, plus cash in lieu of any fractional shares. Because the exchange ratio is fixed, the value of the shares of Comerica common stock that will be issued to you in the merger will depend on the market price of Comerica common stock at the time the shares are issued. There will be no adjustment to the fixed number of shares of Comerica common stock that will be issued to you based upon changes in the market price of Comerica common stock or Sterling common stock prior to the closing. Neither Comerica nor Sterling is permitted to terminate the merger agreement or resolicit the vote of Sterling shareholders solely because of changes in the market prices of either company’s stock.

The market price of Comerica common stock at the time the merger is completed may vary from the price of Comerica common stock on the date the merger agreement was executed, on the date of this proxy statement/prospectus and on the date of the Sterling special meeting as a result of various factors that are beyond the control of Comerica and Sterling, including but not limited to general market and economic conditions, changes in our respective businesses, operations and prospects, and regulatory considerations. In addition to the approval of the merger agreement by Sterling shareholders, completion of the merger is subject to receipt of required regulatory approvals and satisfaction of other conditions that may not occur until after the Sterling special meeting. Therefore, at the time of the Sterling special meeting you will not know the precise value of the consideration you will receive at the effective time of the merger. You should obtain current market quotations for shares of Comerica common stock and for shares of Sterling common stock.

The market price of Comerica common stock after the merger may be affected by factors different from those affecting the shares of Sterling or Comerica currently.

Upon completion of the merger, holders of Sterling common stock will become holders of Comerica common stock. Comerica’s business differs from that of Sterling, and, accordingly, the results of operations of the combined company and the market price of the combined company’s shares of common stock may be affected by factors different from those currently affecting the independent results of operations of each of Comerica and Sterling. For a discussion of the businesses of Comerica and Sterling and of certain factors to consider in connection with those businesses, see the documents incorporated by reference in this proxy statement/prospectus and referred to under “Where You Can Find More Information” beginning on page 82.

Regulatory approvals may not be received, may take longer than expected or impose conditions that are not presently anticipated.

Before the merger may be completed, we must obtain various approvals or consents from the Federal Reserve Board and various bank regulatory and other authorities. These regulators may impose conditions on the completion of the merger or require changes to the terms of the merger. Such conditions or changes could have the effect of delaying completion of the merger or imposing additional costs on or limiting the revenues of Comerica following the merger. See “The Merger—Regulatory Approvals Required for the Merger” beginning on page 46.

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Combining the two companies may be more difficult, costly or time-consuming than expected.

Comerica and Sterling have operated and, until the completion of the merger, will continue to operate, independently. The success of the merger will depend, in part, on our ability to successfully combine the businesses of Comerica and Sterling. To realize these anticipated benefits, after the completion of the merger, Comerica expects to integrate Sterling’s business into its own. It is possible that the integration process could result in the loss of key employees, the disruption of each company’s ongoing businesses or inconsistencies in standards, controls, procedures and policies that adversely affect the combined company’s ability to maintain relationships with clients, customers, depositors and employees or to achieve the anticipated benefits of the merger. The loss of key employees could adversely affect Comerica’s ability to successfully conduct its business in the markets in which Sterling now operates, which could have an adverse effect on Comerica’s financial results and the value of its common stock. If Comerica experiences difficulties with the integration process, the anticipated benefits of the merger may not be realized fully or at all, or may take longer to realize than expected. As with any merger of financial institutions, there also may be business disruptions that cause Sterling to lose customers or cause customers to remove their accounts from Sterling and move their business to competing financial institutions. Integration efforts between the two companies will also divert management attention and resources. These integration matters could have an adverse effect on each of Sterling and Comerica during this transition period and for an undetermined period after consummation of the merger.

Comerica may fail to realize the cost savings estimated for the merger.

Comerica estimates that it will achieve cost savings from the merger when the two companies have been fully integrated. While Comerica continues to be comfortable with these expectations as of the date of this proxy statement/prospectus, it is possible that the estimates of the potential cost savings could turn out to be incorrect. The cost savings estimates also assume Comerica’s ability to combine the businesses of Comerica and Sterling in a manner that permits those cost savings to be realized. If the estimates turn out to be incorrect or Comerica is not able to combine successfully the two companies, the anticipated cost savings may not be fully realized or realized at all, or may take longer to realize than expected.

The fairness opinion obtained by Sterling from its financial advisor will not reflect changes in circumstances between signing the merger agreement and the completion of the merger.

Sterling has not obtained an updated fairness opinion as of the date of this proxy statement/prospectus from Morgan Stanley, Sterling’s financial advisor. Changes in the operations and prospects of Sterling or Comerica, general market and economic conditions and other factors that may be beyond the control of Sterling and Comerica, and on which the fairness opinion was based, may alter the value of Sterling or Comerica or the prices of shares of Sterling common stock or Comerica common stock by the time the merger is completed. The opinion does not speak as of the time the merger will be completed or as of any date other than the date of such opinion. Because Sterling does not anticipate asking its financial advisor to update its opinion, the January 16, 2011 opinion does not address the fairness of the merger consideration, from a financial point of view, at the time the merger is completed. The opinion is included as Annex B to this proxy statement/prospectus. For a description of the opinion that Sterling received from its financial advisor, please refer to “The Merger—Opinion of Morgan Stanley & Co. Incorporated” on page 32. For a description of the other factors considered by Sterling’s board of directors in determining to approve the merger, please refer to “The Merger—Sterling’s Reasons for the Merger; Recommendation of the Sterling Board of Directors” on page 30.

Some of the directors and executive officers of Sterling may have interests and arrangements that may have influenced their decisions to support or recommend that you approve the merger agreement.

The interests of some of the directors and executive officers of Sterling may be different from those of Sterling common shareholders, and directors and officers of Sterling may be participants in arrangements that are different from, or in addition to, those of Sterling common shareholders. These interests are described in more detail in the section of this proxy statement/prospectus entitled “The Merger—Interests of Sterling’s Directors and Executive Officers in the Merger” beginning on page 40.

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The shares of Comerica common stock to be received by Sterling shareholders as a result of the merger will have different rights from the shares of Sterling common stock they currently hold.

Following completion of the merger, holders of Sterling common stock will no longer be shareholders of Sterling, a Texas corporation, but will instead be shareholders of Comerica, a Delaware corporation. The rights associated with Sterling common stock are different from the rights associated with Comerica. See the section of this proxy statement/prospectus entitled “Comparison of Shareholders’ Rights” beginning on page 71.

Sterling shareholders will have a reduced ownership and voting interest after the merger and will exercise less influence over management.

Sterling shareholders currently have the right to vote in the election of the Sterling board of directors and on other matters affecting Sterling. When the merger occurs, each Sterling shareholder that receives shares of Comerica common stock will become a shareholder of Comerica with a percentage ownership of the combined organization that is much smaller than the shareholder’s percentage ownership of Sterling. Because of this, Sterling shareholders will have less influence on the management and policies of Comerica than they now have on the management and policies of Sterling.

Termination of the merger agreement could negatively impact Sterling.

If the merger agreement is terminated, there may be various consequences. For example, Sterling’s businesses may have been impacted adversely by the failure to pursue other beneficial opportunities due to the focus of management on the merger, without realizing any of the anticipated benefits of completing the merger, or the market price of Sterling common stock could decline to the extent that the current market price reflects a market assumption that the merger will be completed. In addition, termination of the merger agreement would increase the possibility of downgrades by Sterling’s credit rating agencies or adverse regulatory actions which could adversely affect Sterling’s businesses. If the merger agreement is terminated and Sterling’s board of directors seeks another merger or business combination, Sterling shareholders cannot be certain that Sterling will be able to find a party willing to pay the equivalent or greater consideration than that which Comerica has agreed to pay in the merger. In addition, if the merger agreement is terminated under certain circumstances, including circumstances involving a change in recommendation by Sterling’s board of directors, Sterling may be required to reimburse Comerica’s expenses, up to a maximum of $3 million, or to pay Comerica a termination fee of $40 million.

Recent legislation regarding the financial services industry may have a significant adverse effect on Comerica’s operations.

On July 21, 2010, the Dodd-Frank Wall Street Reform and Consumer Protection Act, which we refer to as the Dodd-Frank Act, was signed into law. The Dodd-Frank Act implements a variety of far-reaching changes and has been called the most sweeping reform of the financial services industry since the 1930s. Many of the provisions of the Dodd-Frank Act will directly affect Comerica’s ability to conduct its business, including, but not limited to:

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Many provisions in the Dodd-Frank Act remain subject to regulatory rule-making and implementation, the effects of which are not yet known. The provisions of the Dodd-Frank Act and any rules adopted to implement those provisions as well as any additional legislative or regulatory changes may impact the profitability of Comerica’s business activities, may require that Comerica change certain of its business practices, may materially affect its business model or affect retention of key personnel, may require Comerica to raise additional capital and could expose Comerica to additional costs (including increased compliance costs). These and other changes may also require Comerica to invest significant management attention and resources to make any necessary changes and may adversely affect Comerica’s ability to conduct its business as previously conducted or its results of operations or financial condition.

Comerica may be subject to more stringent capital and liquidity requirements.

As discussed above, the Dodd-Frank Act creates a financial stability oversight council that may recommend to the Federal Reserve increasingly strict rules for capital requirements as companies grow in size and complexity and applies the same leverage and risk-based capital requirements that apply to insured depository institutions to most bank holding companies, which, among other things, will, after a three-year phase-in period which begins January 1, 2013, remove trust preferred securities as a permitted component of a holding company’s Tier 1 capital. These requirements, and any other new regulations, could adversely affect Comerica’s ability to pay dividends, or could require Comerica to reduce business levels or to raise capital, including in ways that may adversely affect its results of operations or financial condition.

In addition, on September 12, 2010, the Group of Governors and Heads of Supervision, the oversight body of the Basel Committee on Banking Supervision, announced agreement on the calibration and phase-in arrangements for a strengthened set of capital requirements, known as Basel III. When fully phased in, Basel III will introduce a minimum Tier 1 common equity ratio of 4.5%, net of regulatory deductions, and establish a capital conservation buffer of an additional 2.5% of common equity to risk-weighted assets above the regulatory minimum capital requirement, establishing a minimum common equity ratio plus capital conservation buffer at 7%. This capital conservation buffer will impose capital distribution constraints when the Tier 1 capital ratio falls under 8.5% and the total capital ratio falls under 10.5%. In addition, Basel III introduces a countercyclical capital buffer of up to 2.5% of common equity or other loss absorbing capital above the regulatory capital minimum plus the capital conservation buffer for periods of excess credit growth. Basel III also introduces a non-risk adjusted Tier 1 leverage ratio based on a measure of total exposure rather than total assets, and new liquidity standards. The Basel III capital and liquidity standards will be phased in over a period of several years. The text of the final Basel III capital and liquidity rules was published on December 16, 2010, and is now subject to individual adoption by member nations, including the United States.

Banking regulators could implement changes to the capital adequacy standards applicable to Comerica and Comerica Bank in light of Basel III. The ultimate impact of the new capital and liquidity standards cannot be determined at this time and will depend on a number of factors, including treatment and implementation by the U.S. banking regulators.

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Sterling shareholders do not have dissenters’ appraisal rights in the merger.

Appraisal rights are statutory rights that, if applicable under law, enable shareholders to dissent from an extraordinary transaction, such as a merger, and to demand that the corporation pay the fair value for their shares as determined by a court in a judicial proceeding instead of receiving the consideration offered to shareholders in connection with the extraordinary transaction. Appraisal rights are not available in all circumstances, and exceptions to these rights are provided under the TBOC. In this circumstance, because Comerica’s common stock is listed on the NYSE and Sterling’s common stock is listed on the NASDAQ, Sterling’s shareholders do not have dissenters’ appraisal rights in the merger with respect to their shares of Sterling common stock. See the sections of this proxy statement/prospectus entitled “The Merger—Sterling Shareholders Do Not Have Dissenters’ Appraisal Rights in the Merger” beginning on page 45 and “Comparison of Shareholders’ Rights—Rights of Dissenting Shareholders” beginning on page 78.

Sterling will be subject to business uncertainties and contractual restrictions while the merger is pending.

Uncertainty about the effect of the merger on employees and customers may have an adverse effect on Sterling. These uncertainties may impair Sterling’s ability to attract, retain and motivate key personnel until the merger is completed, and could cause customers and others that deal with Sterling to seek to change existing business relationships with Sterling. Retention of certain employees by Sterling may be challenging while the merger is pending, as certain employees may experience uncertainty about their future roles with Sterling. If key employees depart because of issues relating to the uncertainty and difficulty of integration or a desire not to remain with Sterling, Sterling’s business following the merger could be harmed. In addition, subject to certain exceptions, Sterling has agreed to operate its business in the ordinary course prior to closing. See the section entitled “The Merger Agreement—Covenants and Agreements” beginning on page 53 of this proxy statement/prospectus for a description of the restrictive covenants applicable to Sterling.

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THE STERLING SPECIAL MEETING

This section contains information for Sterling shareholders about the special meeting that Sterling has called to allow its shareholders to consider and approve the merger agreement. We are mailing this proxy statement/prospectus to you, as a Sterling shareholder, on or about [        ]. Together with this proxy statement/prospectus, we are also sending to you a notice of the special meeting of Sterling shareholders and a form of proxy card that Sterling’s board of directors is soliciting for use at the special meeting and at any adjournments or postponements of the special meeting.

This proxy statement/prospectus is also being furnished by Comerica to Sterling shareholders as a prospectus in connection with the issuance of shares of Comerica common stock upon completion of the merger.

Date, Time and Place of Meeting

The special meeting will be held at the offices of Locke Lord Bissell & Liddell LLP, JP Morgan Tower, 600 Travis, 25th Floor Conference Center, Houston, Texas on May 5, 2011, at 1:30 p.m. local time.

Matters to Be Considered

At the special meeting of shareholders, you will be asked to consider and vote upon the following matters:

Recommendation of the Sterling Board of Directors

Sterling’s board of directors determined that the merger, the merger agreement and the transactions contemplated by the merger agreement are advisable and in the best interests of Sterling and its shareholders and has unanimously approved the merger and the merger agreement. Sterling’s board of directors unanimously recommends that Sterling shareholders vote “ FOR ” approval of the merger agreement and “ FOR ” the adjournment proposal. See “The Merger—Sterling’s Reasons for the Merger; Recommendation of the Sterling Board of Directors” on page 30 for a more detailed discussion of the Sterling board of directors’ recommendation.

Record Date and Quorum

Sterling’s board of directors has fixed the close of business on March 30, 2011, as the record date for determining the holders of Sterling common stock entitled to receive notice of and to vote at the Sterling special meeting.

As of the record date, there were 102,118,118 shares of Sterling common stock outstanding and entitled to vote at the Sterling special meeting held by approximately 836 holders of record. Each share of Sterling common stock entitles the holder to one vote at the Sterling special meeting on each proposal to be considered at the Sterling special meeting.

The presence at the special meeting, in person or by proxy, of holders of a majority of the outstanding shares of Sterling common stock entitled to vote at the special meeting will constitute a quorum for the transaction of business. All shares of Sterling common stock, whether present in person or represented by proxy, including abstentions and broker non-votes, will be treated as present for purposes of determining the presence or absence of a quorum for all matters voted on at the Sterling special meeting. A broker non-vote occurs under stock

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exchange rules when a broker is not permitted to vote on a matter without instructions from the beneficial owner of the shares and no instruction is given.

Vote Required; Treatment of Abstentions and Failure to Vote

Approval of the merger agreement requires the affirmative vote of the holders of two-thirds of the outstanding shares of Sterling common stock entitled to vote at the special meeting. You are entitled to one vote for each share of Sterling common stock you held as of the record date. Because approval is based on the affirmative vote of two-thirds of shares outstanding, your failure to vote, failure to instruct your bank or broker with respect to the proposal to approve the merger agreement, or an abstention will have the same effect as a vote against approval of the merger agreement.

Approval of the adjournment proposal requires the affirmative vote of the holders of a majority of shares of Sterling common stock entitled to vote on, and voting for or against or expressly abstaining with respect to, such proposal at the special meeting, even if less than a quorum. Because approval of the adjournment proposal is based on the affirmative vote of a majority of shares voting or expressly abstaining at the special meeting, abstentions will have the same effect as a vote against this proposal. The failure to vote or failure to instruct your bank or broker with respect to the adjournment proposal, however, will have no effect on the adjournment proposal.

Shares Held by Officers and Directors

As of the record date, directors and executive officers of Sterling and their affiliates owned and were entitled to vote 1,944,897 shares of Sterling common stock, representing approximately 1.91% of the shares of Sterling common stock outstanding on that date. Sterling currently expects that its directors and executive officers will vote their shares in favor of the merger agreement proposal and the adjournment proposal, although none of them has entered into any agreements obligating them to do so. As of March 30, 2011, Comerica and its subsidiaries held no shares of Sterling common stock (other than shares held as fiduciary, custodian or agent as described below) and its directors and executive officers or their affiliates held no shares of Sterling common stock. As of March 30, 2011, Comerica and its subsidiaries, as fiduciaries, custodians or agents, held a total of approximately 108,647 shares of Sterling common stock, representing less than 1% of the shares of Sterling common stock outstanding on that date, and maintained sole or shared voting power over approximately 92,979 of these shares. See “The Merger—Interests of Sterling’s Directors and Executive Officers in the Merger” beginning on page 40.

Voting of Proxies; Incomplete Proxies

Each copy of this proxy statement/prospectus mailed to holders of Sterling common stock is accompanied by a form of proxy with instructions for voting. If you hold stock in your name as a shareholder of record, you should complete and return the proxy card accompanying this proxy statement/prospectus, or call the toll-free telephone number or use the Internet as described in the instructions included with your proxy card or voting instruction card, regardless of whether you plan to attend the special meeting.

If you hold your stock in “street name” through a bank or broker, you must direct your bank or broker to vote in accordance with the instructions you have received from your bank or broker.

Sterling shareholders should not send Sterling stock certificates with their proxy cards. After the merger is completed, holders of Sterling common stock will be mailed a transmittal form with instructions on how to exchange their Sterling stock certificates for the merger consideration.

All shares represented by valid proxies (including those given by telephone or the Internet) that we receive through this solicitation, and that are not revoked, will be voted in accordance with your instructions on the proxy

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card. If you make no specification on your proxy card as to how you want your shares voted before signing and returning it, your proxy will be voted “ FOR ” approval of the merger agreement and “ FOR ” approval of the adjournment proposal. No matters other than the matters described in this proxy statement/prospectus are anticipated to be presented for action at the special meeting or at any adjournment or postponement of the special meeting.

Shares Held in Street Name; Broker Non-Votes

Under stock exchange rules, banks, brokers and other nominees who hold shares of Sterling common stock in “street name” for a beneficial owner of those shares typically have the authority to vote in their discretion on “routine” proposals when they have not received instructions from beneficial owners. However, banks, brokers and other nominees are not allowed to exercise their voting discretion with respect to the approval of matters determined to be “non-routine,” such as approval of the merger agreement proposal, without specific instructions from the beneficial owner. Broker non-votes are shares held by a broker, bank or other nominee that are represented at the Sterling special meeting, but with respect to which the broker or nominee is not instructed by the beneficial owner of such shares to vote on the particular proposal and the broker does not have discretionary voting power on such proposal. It is expected that brokers, banks and other nominees will not have discretionary authority to vote on either proposal and, as a result, Sterling anticipates that there will not be any broker non-votes cast in connection with either proposal. Therefore, if your broker, bank or other nominee holds your shares of Sterling common stock in “street name,” your broker, bank or other nominee will vote your shares of Sterling common stock only if you provide instructions on how to vote by filling out the voter instruction form sent to you by your broker, bank or other nominee with this proxy statement/prospectus.

Revocability of Proxies and Changes to a Sterling Shareholder’s Vote

If you hold stock in your name as a shareholder of record, you may revoke any proxy at any time before it is voted by (1) signing and returning a proxy card with a later date, (2) delivering a written revocation letter to Sterling’s corporate secretary, (3) voting again by telephone or the Internet, or (4) attending the special meeting in person, notifying the corporate secretary, and voting by ballot at the special meeting.

Any shareholder entitled to vote in person at the special meeting may vote in person regardless of whether a proxy has been previously given, but the mere presence (without notifying Sterling’s corporate secretary) of a shareholder at the special meeting will not constitute revocation of a previously given proxy.

Written notices of revocation and other communications about revoking your proxy should be addressed to:

Sterling Bancshares, Inc.

2950 North Loop West, Suite 1200

Houston, Texas 77092

Attention: Secretary

If your shares are held in “street name” by a bank or broker, you should follow the instructions of your bank or broker regarding the revocation of proxies.

Participants in Sterling Employee Savings Plan

If you hold shares of Sterling common stock through the Sterling Bancshares, Inc. Employee Savings Plan, you may give voting instructions by completing and returning the enclosed proxy card in the accompanying prepaid reply envelope prior to May 2, 2011. If a participant’s proxy card is not received by May 2, 2011 or if such participant signs and returns his or her proxy card without instructions marked in the boxes, the trustee will vote the participant’s shares of Sterling common stock in the same proportion as other shares of Sterling common stock held in the plan for which the trustee received timely instructions. Participants in the plan must vote through the trustee and may not vote in person at the special meeting.

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With respect to shares of Sterling common stock held by the Sterling Bancshares, Inc. Employee Savings Plan, Charles Schwab Trust Company, the plan’s trustee, is responsible for ensuring that procedures are in place to safeguard the confidentiality of your proxy directions to the trustee and that those procedures are being followed.

Solicitation of Proxies

Sterling will bear the entire cost of soliciting proxies from you. In addition to solicitation of proxies by mail, Sterling will request that banks, brokers, and other record holders send proxies and proxy material to the beneficial owners of Sterling common stock and secure their voting instructions. Sterling will reimburse the record holders for their reasonable expenses in taking those actions. Sterling has also made arrangements with MacKenzie Partners to assist it in soliciting proxies and has agreed to pay them $25,000 plus reasonable expenses for these services. If necessary, Sterling may use several of its regular employees, who will not be specially compensated, to solicit proxies from the Sterling shareholders, either personally or by telephone, facsimile, letter or other electronic means.

Attending the Meeting

All holders of Sterling common stock, including shareholders of record and shareholders who hold their shares through banks, brokers, nominees or any other holder of record, are invited to attend the special meeting. Shareholders of record can vote in person at the special meeting. If you are not a shareholder of record, you must obtain a proxy executed in your favor, from the record holder of your shares, such as a broker, bank or other nominee, to be able to vote in person at the special meeting. If you plan to attend the special meeting, you must hold your shares in your own name or have a letter from the record holder of your shares confirming your ownership. In addition, you must bring a form of personal photo identification with you in order to be admitted. We reserve the right to refuse admittance to anyone without proper proof of share ownership and without proper photo identification. The use of cameras, sound recording equipment, communications devices or any similar equipment during the special meeting is prohibited without Sterling’s express written consent.

Assistance

If you have any questions concerning the merger or this proxy statement/prospectus, would like additional copies of this proxy statement/prospectus or need help voting your shares of Sterling common stock, please contact MacKenzie Partners, Sterling’s proxy solicitor:

MacKenzie Partners

105 Madison Avenue

New York, New York 10016

proxy@mackenziepartners.com

(212) 929-5500 (call collect)

or

(800) 322-2885 (toll free)

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INFORMATION ABOUT THE COMPANIES

Comerica

Comerica is a financial services company incorporated under the laws of the State of Delaware and headquartered in Dallas, Texas. As of December 31, 2010, it was among the 25 largest commercial bank holding companies in the United States. Comerica was formed in 1973 to acquire the outstanding common stock of Comerica Bank, which at such time was a Michigan banking corporation and one of Michigan’s oldest banks (formerly Comerica Bank-Detroit). On October 31, 2007, Comerica Bank, a Michigan banking corporation, was merged with and into Comerica Bank, a Texas banking association, which we refer to as Comerica Bank. As of December 31, 2010, Comerica owned directly or indirectly all the outstanding common stock of two active banking subsidiaries and 48 nonbanking subsidiaries. As of December 31, 2010, Comerica had total assets of approximately $53.7 billion, total deposits of approximately $40.5 billion and total common shareholders’ equity of approximately $5.8 billion. As of December 31, 2010, Comerica and its subsidiaries had 8,636 full-time and 729 part-time employees.

Comerica has strategically aligned its operations into three major business segments (the Business Bank, the Retail Bank, and Wealth & Institutional Management) across four primary geographic markets (the Midwest (Michigan, Ohio and Illinois), Western (California, Arizona, Nevada, Colorado and Washington), Texas and Florida markets). In addition to the three major business segments, the Finance Division is also reported as a segment.

Comerica has two active banking subsidiaries, Comerica Bank and Comerica Bank & Trust, National Association. Comerica has consolidated most of its banking business into Comerica Bank, which is chartered by the State of Texas, and at the state level is supervised and regulated by the Texas Department of Banking. Comerica Bank is a member of the Federal Reserve System and supervised and regulated by the Federal Reserve Bank of Dallas, and has branches in Texas, Michigan, California, Florida and Arizona. Comerica Bank & Trust, National Association is chartered under federal law and is subject to supervision and regulation by the Office of the Comptroller of the Currency. Comerica Bank & Trust, National Association is also a member of the Federal Reserve System. The deposits of Comerica Bank and Comerica Bank & Trust, National Association are insured by the Deposit Insurance Fund of the FDIC to the extent provided by law. Comerica is a bank holding company

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under the Bank Holding Company Act of 1956, as amended, and has elected to become a financial holding company under the provisions of the Gramm-Leach-Bliley Act. Accordingly, Comerica is subject to supervision and regulation at the federal level by the Federal Reserve Board.

Comerica’s principal executive office is located at Comerica Bank Tower, 1717 Main Street, Dallas, Texas 75201, and its telephone number is (214) 462-6831. Comerica’s website can be accessed at http://www.comerica.com. Information contained in Comerica’s website does not constitute part of, and is not incorporated into, this proxy statement/prospectus.

Additional information about Comerica and its subsidiaries is included in documents incorporated by reference in this proxy statement/prospectus. See “Where You Can Find More Information” on page 82 .

Sterling Bancshares, Inc.

Sterling is a bank holding company headquartered in Houston, Texas that has served the banking needs of small to medium-sized businesses for over 36 years. Sterling provides a broad array of financial services to Texas businesses and consumers through 57 banking centers in the greater metropolitan areas of Houston, San Antonio, Dallas and Fort Worth, Texas.

Sterling was incorporated under the laws of the State of Texas in 1980 and became the parent bank holding company of Sterling Bank, a banking association chartered under the laws of the State of Texas, or Sterling Bank, in 1981. Sterling Bank was chartered in 1974 under the laws of the State of Texas. Sterling’s principal executive offices are located at 2950 North Loop West, Suite 1200, Houston, Texas, 77092 and Sterling’s telephone number is (713) 466-8300. Sterling’s website can be accessed at http://www.banksterling.com. Information contained in Sterling’s website does not constitute part of, and is not incorporated into, this proxy statement/prospectus.

At December 31, 2010, Sterling had consolidated total assets of $5.2 billion, total loans of $2.8 billion, total deposits of $4.3 billion, and shareholders’ equity of $622 million.

Additional information about Sterling and its subsidiaries is included in documents incorporated by reference in this proxy statement/prospectus. See “Where You Can Find More Information” on page 82.

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