EQUITY PLEDGE AGREEMENT

Exhibit 10.4

Execution Version

EQUITY PLEDGE AGREEMENT

THIS EQUITY PLEDGE AGREEMENT (this “Agreement”) dated as of this 24 ^th day of October, 2008, between MAIN STREET CAPITAL CORPORATION, a Maryland corporation (the “ Borrower ”), MAIN STREET EQUITY INTERESTS, INC., a Delaware corporation (“ MSEI ” and together with the Borrower, the “ Pledgors ” and each, a “ Pledgor ”), and BRANCH BANKING AND TRUST COMPANY (“ BB&T ”), acting as agent (in such capacity, the “ Administrative Agent ”) for itself and the other Secured Parties (as defined in the Credit Agreement referred to below).

W I T N E S S E T H

WHEREAS, the Administrative Agent and the Lenders (as defined in the Credit Agreement) have agreed to extend credit to Borrower pursuant to the terms of that certain Credit Agreement of even date herewith (as amended, restated, or otherwise modified from time to time, the “ Credit Agreement ”) among the Pledgors, the other Guarantors, the Administrative Agent, the Lenders signatory thereto and BB&T Capital Markets, as Lead Arranger;

WHEREAS, the Pledgors may from time to time enter into or guarantee one or more Hedge Transactions (as defined in the Credit Agreement) with the Hedge Counterparties (as defined in the Credit Agreement);

WHEREAS, each Pledgor beneficially and legally owns the limited liability company membership interests, limited partnership interests, stock and other equity interests in the Guarantor and/or the other Loan Parties and the Subsidiaries (as each such term is defined in the Credit Agreement) described on Schedule I attached hereto (the “ Pledged Entities ”); and

WHEREAS, it is a condition of the Lenders’ agreement to extend credit to Borrower pursuant to the Credit Agreement that the Administrative Agent, on behalf of the Secured Parties (as defined in the Credit Agreement), receive a pledge of the Collateral (as defined below) hereunder by Pledgors’ execution and delivery of this Agreement to secure: (a) the due and punctual payment by Borrower of: (i) the principal of and interest on the Notes (including, without limitation, any and all Revolver Advances), when and as due, whether at maturity, by acceleration, upon one or more dates set for prepayment or otherwise and any renewals, modifications or extensions thereof, in whole or in part; (ii) each payment required to be made by any Pledgor under the Credit Agreement, when and as due, including payments in respect of reimbursement of disbursements, interest thereon, and obligations, if any, to provide cash collateral and any renewals, modifications or extensions thereof, in whole or in part; and (iii) all other monetary obligations of any Pledgor to the Secured Parties under the Credit Agreement and the other Loan Documents to which any Pledgor is or is to be a party and any renewals, modifications or extensions thereof, in whole or in part; (b) the due and punctual performance of all other obligations of any Pledgor under the Credit Agreement

and the other Loan Documents to which such Pledgor is or is to be a party, and any renewals, modifications or extensions thereof, in whole or in part; (c) the due and punctual payment (whether at the stated maturity, by acceleration or otherwise) of all obligations (including any and all Hedging Obligations (as defined in the Credit Agreement) arising under Hedging Agreements and obligations which, but for the automatic stay under Section 362(a) of the Bankruptcy Code, would become due), indebtedness and liabilities of any Pledgor, now existing or hereafter incurred under, arising out of or in connection with any and all Hedging Agreements and any renewals, modifications or extensions thereof (including, all obligations, if any, of any Pledgor as guarantor under the Credit Agreement in respect of Hedging Agreements), and the due and punctual performance and compliance by each Pledgor with all of the terms, conditions and agreements contained in any Hedging Agreements and any renewals, modifications or extensions thereof; (d) the due and punctual payment and performance of all indebtedness, liabilities and obligations of any one or more of Pledgors and the Guarantors arising out of or relating to any Bank Products; (e) the due and punctual payment and performance of all indebtedness, liabilities and obligations of any one or more of Pledgors and the Guarantors arising out of or relating to any Cash Management Services; and (f) the due and punctual payment and performance of all obligations of each of the Guarantors under the Credit Agreement and the other Loan Documents to which they are or are to be a party and any and all renewals, modifications or extensions thereof, in whole or in part (all of the foregoing indebtedness, liabilities and obligations being collectively called the “ Obligations ”).

NOW, THEREFORE, in consideration of the premises and of the mutual covenants herein contained, and for other good and valuable consideration, the receipt and adequacy of which are hereby acknowledged, the parties hereby agree as follows:

SECTION 1. Definitions . Any capitalized terms used but not defined herein shall have the meanings assigned to them in the Credit Agreement.

SECTION 2. Pledge; Perfection .

(a) As collateral security for the due and punctual payment of the Obligations, each Pledgor hereby pledges, hypothecates, delivers and assigns and grants unto Administrative Agent, as agent for itself and the Secured Parties, a security interest (which security interest shall constitute a first priority security interest), in all of Pledgor’s membership interests, limited partnership interests, common stock and other equity interests in the Pledged Entities and all securities instruments or other rights convertible into or exercisable for the foregoing (the “ Equity Interests ”), together with all proceeds, profits, interests, capital accounts, accounts, contract rights, general intangibles, deposits, funds, dividends, distributions, rights to dividends, rights to distributions, including both distributions of money and of property, and other rights, claims and interests relating to or arising out of Pledgor’s Equity Interests, now owned or hereafter acquired, in the Pledged Entities, together with any and all replacements or substitutions for or proceeds of all of the foregoing (collectively, the “ Collateral ”); provided that , notwithstanding anything herein to the contrary, Collateral shall not include, and the security interest herein shall not attach to, (i) the Equity Interests issued by the entities identified as Small Business Investment Corporations on Schedule I , (ii) any outstanding Equity Interests of a Foreign Subsidiary in excess

of 65% of the voting power of all classes of Equity Interests of such Foreign Subsidiary entitled to vote or (iii) any property rights in Equity Interests (other than Equity Interests issued by any Subsidiary), or any Operating Documents of any issuer of such Equity Interests to which Pledgor is a party, or any of its rights or interests thereunder, if the grant of such security interest shall constitute or result in (A) the abandonment, invalidation or unenforceability of any right, title or interest of the Pledgor therein or (B) in a breach or termination pursuant to the terms of, or a default under, any such property rights or Operating Documents (other than to the extent that any such term would be rendered ineffective pursuant to Sections 9-406, 9-407, 9-408 or 9-409 of the UCC (or any successor provisions) of any relevant jurisdiction or any other Applicable Law (including the Bankruptcy Code) or principals of equity) (the Equity Interests described in foregoing clauses (i) through (iii), the “ Excluded Equity Interests ”); provided further that , (x) immediately upon any amendment, modification or repeal of the Restrictive Provisions to allow the pledge of any Excluded Equity Interests of the type described in clause (i), the Collateral shall include, and the security interest granted hereunder shall attach to, such Equity Interests that are no longer subject to such Restrictive Provisions and (y) until such time as attachment occurs with respect to any Excluded Equity Interest of the type described in clause (i) or (iii), references in this Agreement to “Pledged Entities” shall be deemed not to include the issuers of such Excluded Equity Interest.

This Agreement is not intended to place Administrative Agent or any Secured Party in a position of being a member, shareholder or partner of any Pledged Entity, but is intended to grant Administrative Agent, on behalf of the Secured Parties, a lien on and security interest in Pledgor’s Equity Interests in the Pledged Entities including, without limitation, any and all of the Collateral but specifically excluding any general partnership interests.

(b) Each Pledgor hereby delivers to the Administrative Agent (or to the Collateral Custodian as its agent and bailee), on behalf of the Secured Parties, including itself, herewith all certificates, instruments and documents, if any, representing the Equity Interests in the Pledged Entities to be held by the Administrative Agent as Collateral, together with a transfer power in blank duly executed by Pledgor.

SECTION 3. Representations and Warranties . Each Pledgor hereby represents and warrants, as of the date hereof and each day on which a Borrowing is made, that:

(a) Pledgor has all requisite power and authority to enter into this Agreement, to grant a security interest in the Collateral for the purposes described in Section 2 and to carry out the transactions contemplated by this Agreement;

(b) No approval of or consent from any person or entity (other than the acknowledgement and consent of any Pledged Entity which is a Subsidiary as evidenced by its signature hereto) is required in connection with the execution and delivery by Pledgor of this Agreement, the granting and perfection of the security interests in the Collateral, or the carrying out of the transactions contemplated by this Agreement (including the exercise by the Administrative Agent of the voting or other rights provided for in this Agreement or the exercise of remedies in respect thereof);

(c) Pledgor is the record and beneficial owner of the Collateral as of the date hereof;

(d) All of the Collateral is owned by Pledgor free and clear of any pledge, mortgage, hypothecation, lien, charge, encumbrance or any security interest in such Collateral or the proceeds thereof, except for the security interest granted to the Administrative Agent on behalf of the Secured Parties hereunder, and there are no outstanding warrants, options or other rights to purchase, or shareholder, voting trust or similar agreements outstanding with respect to, or property that is convertible into, or that requires the issuance of sale of, any Equity Interests;

(e) The execution, delivery and performance by Pledgor of this Agreement do not and will not contravene or constitute a default under or result in any violation of any agreement (including, without limitation, the operating or partnership agreement of any Pledged Entity), indenture or other instrument, license, judgment, decree, order, law, statute, ordinance or other governmental rule or regulation applicable to Pledgor;

(f) On each Representation Date (as defined in the Security Agreement), Schedule I hereto (as such schedule may be amended or supplemented from time to time pursuant to the terms of this Agreement) sets forth all of the issued and outstanding Equity Interests held by Pledgor and such Equity Interests constitute the percentage of issued and outstanding shares of stock, percentage of membership interests or percentage of partnership interests of the respective Pledged Entities indicated on Schedule I .

(g) Each Pledged Entity is a limited liability company, limited partnership or corporation duly formed, validly existing and in good standing as such under the laws of the jurisdiction of its organization as set forth on Schedule I hereto, and the execution and delivery of this Agreement require no action by or in respect of, or filing with, any governmental body, agency or official (except for the Uniform Commercial Code filings set forth in paragraph (h) below) and do not contravene, or constitute a default under, the operating agreement, partnership agreement, charter or by-laws of any Pledged Entity;

(h) Upon filing of a Uniform Commercial Code Financing Statement with the U.C.C. records of the Secretary of State of the state of organization of each Pledgor, this Agreement creates and grants a valid lien on and perfected security interest in the Collateral and the proceeds thereof, subject to no prior security interest, lien, charge or encumbrance, or to any agreement purporting to grant to any third party a security interest in the property or assets of such Pledgor which would include the Collateral;

(i) A true, correct and complete copy of the operating agreement, limited partnership agreement, charter and by-laws, as the case may be, of each Pledged Entity (together with all amendments thereto) has been provided to the Administrative Agent;

(j) to the extent that any limited liability company interests or partnership interests pledged as Collateral are or represent issuers that have opted to be treated as securities under the applicable U.C.C., the certificates representing such securities have been delivered to the Administrative Agent (or to the Collateral Custodian as its agent and bailee), and no limited liability company interests or partnership interests pledged as Collateral are dealt in or traded on securities exchanges or markets; and

(k) None of the Equity Interests constitutes Margin Stock.

SECTION 4. Voting Rights; Distributions, Etc.

(a) So long as no Event of Default, as defined in the Credit Agreement, shall have occurred and be continuing: