TAX ALLOCATION AGREEMENT

Exhibit 10.01

TAX ALLOCATION AGREEMENT

among

METAVANTE HOLDING COMPANY,

METAVANTE CORPORATION,

NEW M&I CORPORATION

and

MARSHALL & ILSLEY CORPORATION

Dated as of April 3, 2007

TAX ALLOCATION AGREEMENT

TAX ALLOCATION AGREEMENT (this “ Agreement ”), dated as of April 3, 2007, among Metavante Holding Company, a Wisconsin corporation and, as of the date hereof, a wholly-owned subsidiary of MI Corp. (“ MVT Holding ”), Metavante Corporation, a Wisconsin corporation and, as of the date hereof, a wholly-owned subsidiary of MI Corp. (“ MVT Corp. ”) (MVT Holding and MVT Corp., collectively, the “ MVT Parties ”), Marshall & Ilsley Corporation, a Wisconsin corporation (“ MI Corp. ”), and New M&I Corporation, a Wisconsin corporation (“ New MI Corp. ”) (MI Corp. and New MI Corp., collectively, the “ MI Parties ”).

RECITALS

WHEREAS, MI Corp. is the common parent of an affiliated group of corporations within the meaning of Section 1504(a) of the Internal Revenue Code of 1986, as amended (the “ Code ”), which currently files consolidated federal Income Tax Returns (the “ Affiliated Group ”);

WHEREAS, pursuant to the Separation Agreement dated as of the date hereof between the MVT Parties and the MI Parties (as may be amended from time to time in accordance with its terms, the “ Separation Agreement ”) and the Investment Agreement (as defined below), MVT Holding will distribute all of the issued and outstanding shares of New MI Corp. common stock (“ New MI Corp. Common Stock ”) on a pro rata basis to holders of record of MVT Holding Common Stock (as defined in the Investment Agreement) (as described more fully in the Separation Agreement, the “ Distribution ”);

WHEREAS, the MVT Parties, Montana Merger Sub Inc., a Wisconsin corporation and, as of the date hereof, a wholly-owned subsidiary of MVT Holding (“ Merger Sub ”), and the MI Parties have entered into an Investment Agreement, dated as the date hereof (the “ Investment Agreement ”) with WPM, L.P., a Delaware limited partnership (“ Investor ”) pursuant to which, prior to the Distribution, MI Corp. will undertake the MI Merger, the MI Conversion, the MVT Distribution, the MI LLC Contribution and the MI Cash Contribution, and Investor will make the Equity Investment (as defined in the Separation Agreement);

WHEREAS, in connection with the transactions contemplated by the Investment Agreement, one or more of the members of the MVT Group (as defined below) will incur approximately $1.75 billion of indebtedness (the “ Debt Financing ”);

WHEREAS, the parties to this Agreement intend that (i) the MI Merger and the MI Conversion will qualify as a reorganization under Section 368(a)(1)(F) of the Code, (ii) following the MI Merger and the MI Conversion, MVT Holding will become the common parent of the Affiliated Group; (iii) the MI Contribution (as defined in the Investment Agreement) followed by the Distribution will qualify as a reorganization within the meaning of Section 368(a)(1)(D) of the Code; and (iv) the Distribution will qualify as a distribution eligible for nonrecognition under Sections 355(a) and 361(c) of the Code;

WHEREAS, after the Distribution, no member of the MI Group (as defined below) will be a member of the Affiliated Group for federal income tax purposes and MI Corp. will be disregarded as an entity separate from New MI Corp. for U.S. federal income tax purposes;

WHEREAS, after the Distribution the Affiliated Group will continue and MVT Holding will be treated as the common parent of the Affiliated Group for federal income tax purposes; and

WHEREAS, the MVT Group and the MI Group desire on behalf of themselves and their successors to set forth their rights and obligations with respect to Taxes due for periods before, on and after the Distribution Date.

NOW, THEREFORE, in consideration of the premises and of the respective agreements and covenants contained in this Agreement, the parties hereby agree as follows:

ARTICLE I

DEFINITIONS

SECTION 1.01. General . Capitalized terms used in this Agreement have the meanings set forth in this Agreement, or, when not so defined, in the Separation Agreement or the Investment Agreement. As used in this Agreement, the following terms shall have the following meanings (such meanings to be equally applicable to both the singular and plural forms of the terms defined):

“ Affiliate ” has the meaning set forth in the Separation Agreement.

“ Affiliated Group ” has the meaning set forth in the first recital.

“ Agreement ” means this Tax Allocation Agreement as the same may be amended from time to time.

“ Applicable Federal Rate ” means the federal short-term rate under Section 1274(d) of the Code, compounded quarterly.

“ Audit ” means any audit, assessment of Taxes, other examination by any Governmental Entity (as defined in the Investment Agreement), proceeding, or appeal of such a proceeding relating to Taxes, whether administrative or judicial, including proceedings relating to competent authority determinations.

“ Code ” has the meaning set forth in the first recital.

“ Controlling Party ” means the party described as the Controlling Party in accordance with Section 3.01 .

“ Covered Group ” means, in the case of any Covered Group Taxes, the group of Persons that join in the filing of the consolidated, combined or unitary Tax Return upon which such Covered Group Taxes are reported.

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“ Covered Group Taxes ” means any federal, state, local or foreign Taxes reportable on a consolidated, combined or unitary Tax Return for a group that includes any member of the MI Group, on the one hand, and any member of the MVT Group, on the other hand.

“ Covered Group Year ” means, in the case of any Covered Group, any Taxable year of such Covered Group that ends prior to or includes the Distribution Date.

“ Debt Financing ” has the meaning set forth in the fourth recital.

“ Distribution ” has the meaning set forth in the second recital.

“ Distribution Date ” has the meaning set forth in the Separation Agreement.

“ Filing Party ” has the meaning set forth in Section 2.08 .

“ Final Determination ” means with respect to any issue (a) a decision, judgment, decree or other order by any court of competent jurisdiction, which decision, judgment, decree or other order has become final and not subject to further appeal, (b) a closing agreement (whether or not entered into under Section 7121 of the Code) or any other binding settlement agreement (whether or not with the IRS) entered into in connection with or in contemplation of an administrative or judicial proceeding, or (c) the completion of the highest level of administrative proceedings if a judicial contest is not or is no longer available.

“ GAAP ” has the meaning set forth in the Investment Agreement.

“ Income Tax ” means any franchise Tax and any federal, state, local or foreign Tax measured by or imposed on gross receipts or net income or profits. For the avoidance of doubt, the term “Income Tax” shall not include any sales or use Tax.

“ Income Tax Return ” means any Tax Return with respect to Income Taxes.

“ Indemnifiable Losses ” has the meaning set forth in the Separation Agreement.

“ Independent Firm ” has the meaning set forth in Article VI .

“ Information ” has the meaning set forth in the Separation Agreement.

“ Investment Agreement ” has the meaning set forth in the third recital.

“ Investor ” has the meaning set forth in the third recital.

“ Investor Factual Representation ” means the representations of Investor set forth in Section 4.1 of the Investment Agreement and any factual representation provided by Investor in writing in connection with the Tax Opinion described in Section 7.1(f)(ii) of the Investment Agreement.

“ IRS ” means the United States Internal Revenue Service.

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“ Liable Party ” has the meaning set forth in Section 2.08 .

“ MI Corp. ” has the meaning set forth in the preamble.

“ MI Compensation Payments ” has the meaning set forth in Section 2.06(a) .

“ MI Group ” has the meaning set forth in the Separation Agreement.

“ MI Parties ” has the meaning set forth in the preamble.

“ MI Specified Refunds ” means any refunds or credits relating to (i) the transactions described in the complaint filed on March 2, 2007, in the United States District Court for the Eastern District of Wisconsin, (ii) the “Tempest” transactions currently in appeals, and (iii) the amended tax returns filed in connection with securitizations involving auto loans.

“ MI Subsidiary ” has the meaning set forth in the Separation Agreement.

“ MI Taxes ” means any Taxes (excluding Restructuring Taxes) that are treated as MI Taxes under Section 2.05 of this Agreement.

“ New MI Corp. ” has the meaning set forth in the preamble.

“ New MI Corp. Common Stock ” has the meaning set forth in the second recital.

“ MVT Corp. ” has the meaning set forth in the preamble.

“ MVT Compensation Payments ” has the meaning set forth in Section 2.06(a) .

“ MVT Group ” has the meaning set forth in the Separation Agreement.

“ MVT Holding ” has the meaning set forth in the preamble.

“ MVT Parties ” has the meaning set forth in the preamble.

“ MVT Restructuring Tax Audit ” has the meaning set forth in Section 3.02(a) .

“MVT Separate Group Basis ” means, in the case of any Covered Group Taxes for a Covered Group Year, the amount of such Covered Group Taxes for such Covered Group Year that would have been due if the underlying Covered Group consisted solely of members of the MVT Group and did not include any members of the MI Group and computed (i) by taking into account elections and accounting methods actually used in computing such Covered Group Taxes for such Covered Group Year, (ii) with appropriate adjustments to take into account the application of Treasury Regulations Section 1.1502-13 or similar provisions of state and local Tax law to any intercompany transactions between members of the MVT Group (on one hand) and members of the MI Group (on the other hand), (iii) consistent with past practice (including past practice of allocating state and local unitary Taxes and expenses to an entity if that entity caused the filing of a combined, consolidated or unitary Tax Return) and (iv) with such other adjustments as are contemplated by this Agreement; provided , however , that Tax liability for an entity with nexus in a combined return state shall be based on that entity’s relative apportionment percentage of the total apportionment percentage of the actual combined group.

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“ MVT Subsidiary ” has the meaning set forth in the Separation Agreement.

“ MVT Tainting Act ” means:

(a) any action (or failure to take any reasonably available action) by any of the MVT Parties or any Affiliate of the MVT Parties after the Distribution Date other than an action contemplated by the Investment Agreement or any of the Transaction Agreements;

(b) any inaccuracy of any Investor Factual Representation;

(c) any acquisition or other transaction involving the equity of any of the MVT Parties or any Affiliate of the MVT Parties (other than the distribution of the New MI Corp. Common Stock in the Distribution or the Equity Investment); or

(d) any Prohibited Act performed by any of the MVT Parties or any Affiliate of the MVT Parties after the Distribution Date.

“ MVT Taxes ” means any Taxes (excluding Restructuring Taxes) that are treated as MVT Taxes under Section 2.05 of this Agreement.

“ Past Practice ” has the meaning set forth in Section 2.01(e) .

“ Person ” has the meaning set forth in the Investment Agreement.

“ Post-Distribution Period ” means any Taxable year or other Taxable period beginning after the Distribution Date and, in the case of any Taxable year or other Taxable period that begins on or before and ends after the Distribution Date, that part of the Taxable year or other Taxable period that begins at the beginning of the day after the Distribution Date.

“ Pre-Distribution Period ” means any Taxable year or other Taxable period that ends on or before the close of the Distribution Date and, in the case of any Taxable year or other Taxable period that begins on or before and ends after the Distribution Date, that part of the Taxable year or other Taxable period through the close of the Distribution Date.

“ Private Letter Ruling ” has the meaning set forth in the Investment Agreement.

“ Prohibited Acts ” has the meaning specified in Section 4.02(a) .

“ Restricted Period ” has the meaning specified in Section 4.02(a) .

“ Restructuring Taxes ” means any Taxes (and other liabilities, including liability to stockholders and the costs of defending against the imposition of such Taxes and other liabilities) of any member of the MVT Group or the MI Group arising from or attributable to one or more of the Transactions (as defined in the Investment Agreement), including but not limited to (a) any failure of the Distribution to constitute a distribution eligible for nonrecognition under

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Sections 355(a) and 361(c), (b) any failure of the MI Contribution (as defined in the Investment Agreement) followed by the Distribution to qualify as a reorganization within the meaning of Section 368(a)(1)(D) of the Code, or (c) any failure of any stock of New MI Corp. to be treated as “qualified property” within the meaning of Section 355(c)(2) or Section 361(c)(2) of the Code because of the application of Section 355(d) or Section 355(e) of the Code to the Distribution; provided , however , that Restructuring Taxes shall not include any Taxes imposed on the MVT Dividend or any distributions of cash from Subsidiaries to fund the MVT Dividend (which Taxes are governed by Section 2.04(d) ).

“ Separation Agreement ” has the meaning set forth in the second recital.

“ Shared Return ” means a Tax Return described in clause (a) of Section 2.01 .

“ Subsidiary ” has the meaning set forth in the Separation Agreement.

“ Tax ” (and, with correlative meaning, “Taxes” and “Taxable”) has the meaning set forth in the Investment Agreement.

“ Tax Carryover Attribute ” has the meaning specified in Section 2.07 .

“ Tax Item ” means any item of income, gain, loss, deduction or credit, or other attribute that may have the effect of increasing or decreasing any Tax.

“ Tax Opinion ” means the tax opinion described in Section 7.1(f)(ii) of the Investment Agreement.

“ Tax Return ” has the meaning set forth in the Investment Agreement.

“ Transaction Agreements ” has the meaning set forth in the Investment Agreement.

“ Transaction Taxes ” has the meaning set forth in Section 2.04(b) .

ARTICLE II

TAX RETURNS, TAX PAYMENTS AND TAX SHARING OBLIGATIONS

SECTION 2.01. Obligations to File Tax Returns .

(a) From and after the Distribution Time, New MI Corp. shall prepare and timely file or cause to be timely filed all original Income Tax Returns with respect to any member of the MVT Group for any Taxable year ending on or before December 31, 2007 (including any original Income Tax Return for any Covered Group Taxes for any Taxable year ending on or before December 31, 2007), whether or not such Income Tax Return includes any member of the MI Group. To the extent a member of the MI Group is legally unable to sign any such Income Tax Return, MVT Holding shall sign or cause to be signed such Income Tax Return. The MVT Parties shall reimburse New MI Corp. for any Costs (as defined in Section 3.01 ) incurred by MI Corp. in preparing any Income Tax Return to the extent such Cost is attributable to the portion of such Income Tax Return relating to any member of the MVT Group.

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(b) From and after the Distribution Time, New MI Corp. shall in addition to the Income Tax Returns described in clause (a), prepare and timely file or cause to be timely filed any other Tax Return with respect to any member of the MI Group.

(c) From and after the Distribution Time, MVT Holding shall prepare and timely file or cause to be timely filed any Tax Returns (other than an Income Tax Return described in clause (a)) with respect to any member of the MVT Group (including, but not limited to, the federal consolidated Income Tax Return and state Income Tax Returns for the taxable year beginning January 1, 2008).

(d) For the avoidance of doubt, the provisions of this Section 2.01 apply only to the preparation and filing of Tax Returns. Each party shall be responsible for its own financial reporting, including but not limited to calculating and booking provisions for Income Taxes for GAAP purposes.

(e) All Income Tax Returns relating to any member of the MVT Group for Taxable years or periods ending on or before December 31, 2007 shall (to the extent permitted by Applicable Laws) be prepared on a basis consistent with the elections, methods of accounting, positions, conventions and principles of taxation and the manner in which any Tax item or other information is reported as reflected in comparable Income Tax Returns filed before the date of this Agreement (the manner in which so reported, “ Past Practice ”), provided that a different method can be used (x) if it would not increase Taxes for which the MVT Parties would be responsible under this Agreement or (y) with the prior written consent of MVT Holding (such consent not to be unreasonably withheld); provided further that if there is no Past Practice with respect to a material Tax item or other information to be reported on an Income Tax Return relating to any member of the MVT Group for Taxable years or periods ending on or before December 31, 2007, then New MI Corp. and MVT Holding shall mutually agree on the manner in which such Tax item or other information is reported. The preceding sentence shall not apply (i) to the extent otherwise contemplated or required by the Private Letter Ruling, or (ii) if there has been a change in Applicable Laws. Consent shall not be considered unreasonably withheld within the meaning of the second preceding sentence if such different method would increase Taxes for which the MVT Parties would be responsible under this Agreement and for which New MI Corp. does not compensate the MVT Parties. New MI Corp. shall (A) make available to MVT Holding any Shared Return it is responsible for filing at least 10 calendar days prior to filing, provided that MVT Holding shall supply New MI Corp. with all information regarding any member of the MVT Group reasonably necessary for preparing such Shared Return at least 100 calendar days prior to the due date for filing such Shared Return, and (B) make reasonable revisions to such Shared Returns that are requested by MVT Holding.

SECTION 2.02. Obligation to Remit Taxes . Following the Distribution Date, (a) New MI Corp. shall timely remit or cause to be remitted any Taxes due in respect of any Tax Return it or any member of the MI Group is required to file under applicable law (without regard to this Agreement), and (b) MVT Holding shall timely remit or cause to be remitted any Taxes due in respect of any Tax Return it or any member of the MVT Group is required to file under applicable law (without regard to this Agreement). To the extent a remittance by New MI Corp. includes any MVT Taxes, MVT Holding shall advance funds to New MI Corp. at least one (1) day prior to the date New MI Corp. is required to make such remittance, and to the extent a

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remittance by MVT Holding includes any MI Taxes, New MI Corp. shall advance funds to MVT Holding at least one (1) day prior to the date MVT Holding is required to make such remittance. For the avoidance of doubt, this Section 2.02 governs only the party responsible for making the initial remittance to a Taxing Authority and shall not govern the determination of whether the Taxes remitted are an MI Tax or an MVT Tax.

SECTION 2.03. Tax Indemnity; Prior Agreements; Refunds .

(a) From and after the Distribution Time, the MI Parties shall, in a manner consistent with the principles of Section 4.03 of the Separation Agreement, reimburse, indemnify, defend, and hold harmless the MVT Indemnified Parties from and against, any and all Indemnifiable Losses incurred or suffered by one or more of the MVT Indemnified Parties in connection with, relating to, arising out of, or due to, directly or indirectly, (i) any MI Taxes (including, for the avoidance of doubt, any MI Taxes arising from a redetermination thereof from an audit or examination); and (ii) any amount for which New MI Corp. is liable under Section 2.04 .

(b) From and after the Distribution Time, the MVT Parties shall, in a manner consistent with the principles of Section 4.02 of the Separation Agreement, reimburse, indemnify, defend, and hold harmless the MI Indemnified Parties from and against, any and all Indemnifiable Losses incurred or suffered by one or more of the MI Indemnified Parties in connection with, relating to, arising out of, or due to, directly or indirectly, (i) any MVT Taxes (including, for the avoidance of doubt, any MVT Taxes arising from a redetermination thereof from an audit or examination); and (ii) any amount for which MVT Holding is liable under Section 2.04 .

(c) Any and all prior Tax sharing agreements or practices between any member of the MVT Group, on the one hand, and any member of the MI Group, on the other hand, shall automatically be terminated as of the Distribution Date (other than any such agreements set forth in the Transaction Agreements). Upon termination of the existing tax allocation agreement between MI Corp. and MVT Corp., MVT Corp. shall pay to MI Corp. $730,000 in full satisfaction of any and all amounts due thereunder.

(d) From and after the Distribution Time, the MVT Parties shall be entitled to any refund of or credit for MVT Taxes, provided that the MI Parties shall be entitled to receive and retain any refund of Taxes to the extent such refund is attributable to a Tax Carryover Attribute of any member of the MI Group. From and after the Distribution Time, the MI Parties shall be entitled to any refund of or credit for Taxes to which the MVT Parties are not entitled pursuant to the preceding sentence.

(e) For the avoidance of doubt, (i) any MI Specified Refunds are solely for the benefit of the MI Parties, (ii) any payroll Tax refunds arising out of the Supreme Court’s decision in CSX Corp. v. United States shall be for the benefit of the MI Parties if a member of the MI Group incurred the payroll expense and for the benefit of the MVT Parties if a member of the MVT Group incurred the payroll expense, and (iii) any sales or use Tax Refunds shall be for the benefit of the MI Parties if a member of the MI Group incurred the original sales or use Tax and for the benefit of the MVT Parties if a member of the MVT Group incurred the original sales or use Tax.

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SECTION 2.04. Restructuring Taxes; Other Taxes Relating to the Distribution .

(a) Except to the extent otherwise provided in Section 2.04(b) , (i) the MVT Parties shall be liable for any Restructuring Tax to the extent such Restructuring Tax would not have been imposed but for an MVT Tainting Act and (ii) the MI Parties shall be liable for any other Restructuring Taxes.

(b) The MVT Parties shall be liable for 50% and the MI Parties shall be liable for 50% of any sales, transfer, value added or other similar Taxes or fees (including all real estate, transfer Taxes and real estate recording fees but excluding patent, copyright, and trademark recording fees and similar items relating to patents, copyrights and trademarks (which are governed by Section 6.6 of the Investment Agreement)) payable in connection with the transactions contemplated by the Separation Agreement and the Investment Agreement (the “ Transaction Taxes ”). The parties agree to timely sign and deliver such certificates or forms as are requested by the other party and may be necessary or appropriate to enable such party to file promptly and timely the Tax Returns for such Transaction Taxes with the appropriate Taxing authorities and remit payment of the Transaction Taxes.

(c) Notwithstanding any other provision of this Agreement, the MI Parties shall be liable for all Taxes arising from or attributable to (i) any excess loss accounts or deferred intercompany transactions taken into account under Section 1502 of the Code or Treasury Regulations issued thereunder and any similar items (including but not limited to “deferred intercompany stock accounts” for California tax purposes) taken into account under state, local or foreign Tax laws as a result of the transactions contemplated by the Separation Agreement and the Investment Agreement (but not, for the avoidance of doubt, any excess loss accounts created as a result of such transactions that are not taken into account as a result of such transactions), (ii) Sections 301(c)(3), 311(b) or 357(c) of the Code and any similar provisions of state, local and foreign Tax law as a result of the transactions contemplated by the Separation Agreement or the Investment Agreement, and (iii) recapture of any “dual consolidated losses” attributable to any member of the MI Group within the meaning of Section 1503 of the Code.

(d) Notwithstanding any other provision of this Agreement, the MI Parties shall be liable for all Taxes imposed on the MVT Dividend or any distributions of cash from Subsidiaries to fund the MVT Dividend; provided , however , that the MVT Parties shall be liable for any such Taxes to the extent such Taxes would not have been imposed but for any structural chan