SECURITY AGREEMENT

THIS SECURITY AGREEMENT, dated as of the 31st day of December, 2007 (the
“Agreement”), is made among MAIN STREET CAPITAL CORPORATION, a Maryland
corporation (the “Grantor”), and BRANCH BANKING AND TRUST COMPANY (“BB&T”),
acting as agent (in such capacity, the “Administrative Agent”) for itself and
for the other Secured Parties as defined herein.

W I T N E S S E T H
:

RECITALS:

WHEREAS, the Administrative Agent and the Lenders (as defined in the Credit
Agreement defined below) have agreed to extend credit to the Borrower (as
defined in the Credit Agreement) pursuant to the terms of that certain Treasury
Secured Revolving Credit Agreement of even date herewith (as amended, restated,
or otherwise modified from time to time, the “Credit Agreement”) among the
Grantor, the initial guarantor party thereto, the Administrative Agent and the
Lenders signatory thereto;

WHEREAS, the obligations of the Administrative Agent and the Lenders to extend
credit under the Credit Agreement and the other Loan Documents are conditioned
upon, among other things, the execution and delivery by the Grantor of a
security agreement in the form hereof to secure (a) the due and punctual payment
by the 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 the Borrower 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 the Borrower to the Secured
Parties under the Credit Agreement and the other Loan Documents to which the
Borrower 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 the Borrower under the Credit Agreement and the other Loan
Documents to which the Borrower is or is to be a party, and any renewals,
modifications or extensions thereof, in whole or in part; and (c) the due and
punctual payment and performance of all obligations of the Guarantor 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 the foregoing indebtedness, liabilities and obligations being
collectively called the “Obligations”).

NOW, THEREFORE, in consideration of the premises and other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged by
the Grantor and the Administrative Agent, the parties agree as follows:

1. Definitions. As herein used, the following terms shall have the following
meanings:

(a) “Cash Collateral” shall have the meaning set forth in the Credit Agreement.

(b) “Collateral” means all of Grantor’s rights in and to each of the following,
whether now owned or held by Grantor or hereafter acquired: (i) the Securities
Account and any and all assets and other property, tangible or intangible, now
existing or hereafter arising, maintained in, credited to or recorded in the
Securities Account, including without limitation any and all Investment
Property, Treasury Securities, securities and other financial assets maintained
in, recorded in, credited to or contained therein (including, without
limitation, the Cash Collateral); (ii) any and all Security Entitlements with
respect to the financial assets maintained in, recorded in or credited to the
Securities Account; (iii) any and all other Investment Property or assets from
time to time maintained in, credited to or recorded in the Securities Account;
(iv) any and all cash and cash equivalents from time to time maintained in,
credited to or recorded in the Securities Account; (v) all Supporting
Obligations which relate to, arise from or are in connection with the assets
maintained in, credited to or recorded in the Securities Account; (vi) all
replacements or substitutions for any of the foregoing; and (vii) all proceeds
and products of any of the foregoing and the proceeds and products of other
proceeds and products. The parties hereby expressly agree that all property at
any time held in the Securities Account is to be treated as a “finanical asset.”

(c) “Credit Documents” means the Credit Agreement, the Notes, the Collateral
Documents and all other Loan Documents.

(d) “Event of Default” shall have the meaning assigned to it in Section 6
hereof.

(e) “Executive Office” shall have the meaning assigned to it in Section 5
hereof.

(f) “Financial Assets” means any and all financial assets (as that term is
defined in the U.C.C.).

(g) “Investment Property” means any and all investment property (as that term is
defined in the U.C.C.).

(h) “Obligations” has the meaning set forth in the Recitals.

(i) “Person” means an individual, a corporation, a limited liability company, a
government or governmental subdivision or agency or instrumentality, a business
trust, an estate, a trust, a partnership, a cooperative, an association, two or
more Persons having a joint or common interest or any other legal or commercial
entity.

(j) “Proceeds” means any and all proceeds (as that term is defined in the
U.C.C.), including without limitation, whatever is received when Collateral is
sold, exchanged, collected or otherwise disposed of.

(k) “Secured Parties” means collectively (a) the Lenders party to the Credit
Agreement, and (b) the Administrative Agent in its capacity as such under the
Credit Agreement, this Agreement, the Collateral Documents and each other Loan
Document, and (c) the successors and assigns of the foregoing.

(l) “Securities Account” means that certain securities account no. 1582000060
and all subaccounts related thereto maintained with or held by Securities
Intermediary pursuant to an agreement between Securities Intermediary and
Grantor dated as of December 31, 2007 and any and all modifications,
supplements, consolidations, renewals and substitutions thereto or replacements
thereof.

(m) “Security Entitlement” means any and all securities entitlements (as that
term is defined in the U.C.C.).

(n) “Securities Intermediary” means Branch Banking and Trust Company, by and
through its Corporate Trust Services Department.

(o) “Supporting Obligations” means any and all supporting obligations (as that
term is defined in the U.C.C.).

(p) “Treasury Securities” shall mean Treasury Securities of the United States
maturing within 90 days of the date of acquisition thereof.

(q) “U.C.C.” means the Uniform Commercial Code as in effect in the State of
North Carolina.

Terms used herein and not otherwise defined herein shall have the meanings set
forth in the Credit Agreement. The rules of interpretation specified in
Section 9.15 of the Credit Agreement shall be applicable to this Agreement.

2. Security Interest. In consideration of and in order to secure the
fulfillment, satisfaction, payment and performance of all of the Obligations,
the Grantor hereby assigns, pledges, hypothecates and sets over to the
Administrative Agent, its successors and its assigns, for the benefit of the
Secured Parties, and grants to the Administrative Agent, its successors and its
assigns, for the benefit of the Secured Parties, a security interest in all of
the Collateral.

3. Care of Collateral. The Grantor has the risk of loss of the Collateral. The
Administrative Agent shall have no duty of care with respect to the Collateral,
except that the Administrative Agent shall exercise reasonable care with respect
to Collateral in its custody, but shall be deemed to have exercised reasonable
care if such property is accorded treatment substantially equal to that which
the Administrative Agent accords its own property, or if the Administrative
Agent takes such action with respect to the Collateral as a Grantor shall
request in writing but no failure to comply with any such request nor any
omission to do any such act requested by a Grantor shall be deemed a failure to
exercise reasonable care, nor shall the Administrative Agent’s failure to take
steps to collect any income accruing on the Collateral or to preserve rights
against any parties or property be deemed a failure to have exercised reasonable
care with respect to Collateral in its custody. The rights and security interest
herein provided are granted as security only and shall not subject the
Administrative Agent or any Secured Party to, or in any way alter or modify, any
obligation or liability of the Grantor with respect to or arising out of any of
the Collateral.

4. [Intentionally deleted]

5. Representations, Warranties and Covenants as to Collateral.

The Grantor represents, warrants and covenants to and for the benefit of the
Administrative Agent and the Secured Parties as of the date hereof and as of the
date of each Advance under the Credit Agreement that:

(a) Cash Collateral. Any Cash Collateral included in the calculation of the Cash
Collateral Coverage Ratio under the Credit Agreement constitute Collateral as
defined herein.

(b) Good Title; No Existing Encumbrances. The Grantor owns the Collateral free
and clear of any prior lien, and no financing statements or other evidences of
the grant of a security interest respecting the Collateral exist on the public
records.

(c) Right to Grant Security Interest; No Further Encumbrances. The Grantor has
the right to grant a security interest in the Collateral. Except as permitted by
the Credit Agreement, the Grantor will pay all taxes and other charges against
the Collateral, and the Grantor will not use the Collateral illegally or allow
the Collateral to be encumbered.

(d) Location of Collateral; Location of Executive Office. The Grantor hereby
represents and warrants to the Administrative Agent and the Lenders that, as of
the date hereof, the Collateral is entirely contained within, recorded in, or
credited to, the Securities Account, and the Grantor covenants with the
Administrative Agent not to transfer the Collateral to any other account. The
executive office of the Grantor set forth on Schedule I hereto (the “Executive
Office”) is the Grantor’s chief executive office (if the Grantor has more than
one place of business).

(e) Collateral Status. The Grantor will promptly notify the Administrative Agent
if there is any adverse change in the status of the Collateral that would
reasonably be expected to have a Material Adverse Effect.

(f) Delivery of Certain Collateral. Upon the reasonable request of the
Administrative Agent, the Grantor shall deliver all items the physical
possession of which is necessary in order for the Administrative Agent, on
behalf of the Secured Parties, to perfect or preserve the priority of its
security interest in the Collateral.

(g) Records Respecting Collateral. The Grantor shall keep complete and accurate
books and records and make all necessary entries thereon to reflect the
transactions and facts giving rise to the Collateral and payments, credits and
adjustments applicable thereto, all in accordance with GAAP. All books and
records of the Grantor with respect to the Collateral will be accessible from
the Executive Office (as it may be changed pursuant to Section 5(c)).

(h) Further Assurances. The Grantor shall execute and/or deliver (or cause to be
executed and/or delivered) to the Administrative Agent and Secured Parties any
instrument, document, financing statement, assignment, waiver, consent or other
writing reasonably requested by the Administrative Agent which may be reasonably
necessary to the Administrative Agent to carry out the terms of this Agreement
and any of the other Loan Documents and to perfect its security interest in and
facilitate the collection of the Collateral, the proceeds thereof, and any other
property at any time constituting security to the Secured Parties. The Grantor
shall perform or cause to be performed such acts as the Administrative Agent or
any Secured Party may reasonably request to establish and maintain for the
Administrative Agent and the Secured Parties a valid and perfected security
interest in and security title to the Collateral, free and clear of any liens.

(i) Maintenance of Insurance. Grantor shall maintain, or cause to be maintained,
insurance as required under the Credit Agreement. The Grantor shall deliver to
the Administrative Agent on or before the date of the first Borrowing under the
Credit Agreement, and at such other times as the Administrative Agent may
request, a detailed list of such insurance then in effect stating the names of
the insurance companies, the amounts and rates of insurance, the date of
expiration thereof, the properties and risks covered thereby and the insured
with respect thereto. The Grantor will pay all premiums on the insurance
referred to herein as and when they become due and shall do all things necessary
to maintain the insurance in effect.

(j) Change of Chief Executive Office. The Grantor hereby understands and agrees
that if, at any time hereafter, the Grantor elects to move its Executive Office,
or if the Grantor elects to change its name, identity, state of incorporation or
organization, or its structure to other than as existing on the date hereof, the
Grantor will notify the Administrative Agent in writing at least thirty
(30) days prior thereto.

(k) Control Agreements. The Grantor will obtain and deliver or cause to be
delivered to the Administrative Agent, an account control agreement in form and
substance satisfactory to Administrative Agent with respect to the Securities
Account (“Control Agreement”).

(l) Business Purpose. None of the Obligations is a Consumer Transaction, as
defined in the U.C.C. and none of the Collateral has been or will be purchased
or held primarily for personal, family or household purposes.

6. Events of Default. The happening of any one or more of the following events
shall constitute an Event of Default hereunder: (a) the nonpayment when due of
any of the Obligations which nonpayment is not fully cured within the applicable
grace period therefor, if any, or (b) the occurrence of an Event of Default (as
defined in the Credit Agreement).

7. Remedies. Upon the occurrence of an Event of Default and during the
continuation thereof, the Administrative Agent shall have all of the rights and
remedies available at law (including, without limitation, those provided to a
secured party by the U.C.C.), or in equity to collect, enforce or satisfy any
Obligations then owing, whether by acceleration or otherwise. In addition
thereto, the Grantor further agrees that (i) in the event that notice is
necessary under applicable law, written notice mailed to Grantor at the
Grantor’s address given below, ten (10) business days prior to the date of sale
of any of the Collateral subject to the security interest created herein or
prior to the date after which private sale or any other disposition of said
Collateral will be made shall constitute reasonable notice, but notice given in
any other reasonable manner or at any other time shall be sufficient; (ii) in
the event of sale or other disposition of any such Collateral, the
Administrative Agent may apply the proceeds of any such sale or disposition to
the satisfaction of the Administrative Agent’s reasonable attorneys’ fees, legal
expenses, and other costs and expenses incurred in connection with the
Administrative Agent’s taking, retaking, holding, preparing for sale, and
selling of the Collateral; (iii) without precluding any other methods of sale,
the sale of Collateral shall have been made in a commercially reasonable manner
if conducted in conformity with reasonable commercial practices of banks
disposing of similar property but in any event the Administrative Agent may sell
on such terms as the Administrative Agent may choose, without assuming any
credit risk and without any obligation to advertise or give notice of any kind;
and (iv) the Administrative Agent may comply with any applicable state or
federal law requirements in connection with a disposition of the Collateral and
compliance will not be considered adversely to affect the commercial
reasonableness of any sale of the Collateral. Furthermore, in any such event, to
the extent permitted under applicable law, full power and authority are hereby
given the Administrative Agent to sell, assign, and deliver the whole of the
Collateral or any part(s) thereof, at any time(s) at any broker’s board, or at
public or private sale, at the Administrative Agent’s option, and no delay on
the Administrative Agent’s part in exercising any power of sale or any other
rights or options hereunder, and no notice or demand, which may be given to or
made upon any or all of the Grantor by the Administrative Agent or any Secured
Party with respect to any power of sale or other right or option hereunder,
shall constitute a waiver thereof, or limit or impair the Administrative Agent’s
right to take any action or to exercise any power of sale or any other rights
hereunder, without notice or demand, or prejudice the Administrative Agent’s
rights as against the Grantor in any respect. The Grantor hereby waives and
releases to the fullest extent permitted by law any right or equity of
redemption with respect to the Collateral, whether before or after sale
hereunder, and all rights, if any, of marshaling the Collateral and any other
security for the Obligations or otherwise. At any such sale, unless prohibited
by applicable law, the Administrative Agent may bid for and purchase all or any
part of the Collateral so sold free from any such right or equity of redemption.
If Administrative Agent sells any of the Collateral upon credit, the Grantor
will be credited only with payments actually made by the purchaser, received by
the Administrative Agent and applied to the indebtedness of the purchaser. In
the event the purchaser fails to pay for the Collateral, the Administrative
Agent may resell the Collateral and the Grantor shall be credited with the
proceeds of the sale as and when received, less expenses. In the event the
Administrative Agent purchases any of the Collateral being sold, the
Administrative Agent may pay for the Collateral by crediting some or all of the
Obligations of the Grantor. The Administrative Agent shall not be liable for
failure to collect or realize upon any or all of the Collateral or for any delay
in so doing nor shall the Administrative Agent be under any obligation to take
any action whatsoever with regard thereto. The Administrative Agent has no
obligation to attempt to satisfy the Obligations by collecting them from any
other person liable for them and the Administrative Agent may release, modify or
waive any collateral provided by any other Person to secure any of the
Obligations, all without affecting the Administrative Agent’s rights against the
Grantor. The Grantor waives any right it may have to require the Administrative
Agent to pursue any third Person for any of the Obligations. The Administrative
Agent may sell the Collateral without giving any warranties as to the Collateral
and may specifically disclaim any warranties of title or the like. This
procedure will not be considered adversely to affect the commercial
reasonableness of any sale of the Collateral.

8. Continuing Security Interest. Any and all of the Administrative Agent’s
rights with respect to the security interests hereunder shall continue
unimpaired until the Obligations have been fully paid and the Lenders’
obligations to extend credit to Grantor under the Credit Agreement have
irrevocably terminated, and the Grantor shall be and remain obligated in
accordance with the terms hereof, notwithstanding the release or substitution of
any Collateral at any time or of any rights or interests therein, or any delay,
extension of time, renewal, compromise or other indulgence granted by the
Administrative Agent or any Secured Party in reference to any of the
Obligations, or any promissory note or instrument or Credit Document given in
connection therewith, the Grantor hereby waiving all notice of any such delay,
extension, release, substitution, renewal, compromise or other indulgence, and
hereby consenting to be bound thereby as fully and effectually as if the Grantor
had expressly agreed thereto in advance.

9. No Waiver. No delay on the Administrative Agent’s part in exercising any
power of sale, option or other right hereunder, and no notice or demand which
may be given to or made upon the Grantor by the Administrative Agent, shall
constitute a waiver thereof, or limit or impair the Administrative Agent’s right
to take any action or to exercise any other power of sale, option or any other
right hereunder, without notice or demand, or prejudice the Administrative
Agent’s rights as against the Grantor in any respect.

10. Financing Statements. The Grantor hereby irrevocably authorizes the
Administrative Agent at any time and from time to time to file in any relevant
jurisdiction any initial financing statements with respect to the Collateral or
any part thereof and amendments thereto that contain the information required by
the U.C.C. of each applicable jurisdiction for the filing of any financing
statement or amendment, including (i) whether the Grantor is an organization,
the type of organization and any organizational identification number issued to
the Grantor, and (ii) a description of collateral that describes such property
in any other manner as the Administrative Agent may reasonably determine is
necessary or advisable to ensure the perfection of the security interest in the
Collateral granted under this Agreement. The Grantor agrees to provide such
information to the Administrative Agent promptly upon request. The Grantor
agrees to reimburse the Administrative Agent for the expense of any such filings
in any location deemed necessary and appropriate by the Administrative Agent. To
the extent lawful, the Grantor hereby appoints the Administrative Agent as its
attorney-in-fact (without requiring the Administrative Agent to act as such) to
perform all other acts that the Administrative Agent deems appropriate to
perfect and continue its security interest in, and to protect and preserve, the
Collateral.

11. Power of Attorney. Effective after the occurrence of an Event of Default and
during the continuation thereof, the Grantor hereby appoints any officer or
agent of the Administrative Agent as the Grantor’s true and lawful
attorney-in-fact with power to endorse the name of the Grantor upon any
instruments of payment or Collateral which may come into possession of the
Administrative Agent; to give written notice to such office and officials of the
United States Postal Service to affect such change or changes of address so that
all mail addressed to any or all Grantor may be delivered directly to the
Administrative Agent (the Administrative Agent will return all mail not related
to the Obligations or the Collateral); granting unto the Grantor’s said attorney
full power to do any and all things necessary to be done with respect to the
above transactions as fully and effectively as the Grantor might or could do,
and hereby ratifying all its said attorney shall lawfully do or cause to be done
by virtue hereof. This power of attorney shall be irrevocable for the term of
this Agreement and all transactions hereunder.

12. Remedies, Etc., Cumulative. Each right, power and remedy of the
Administrative Agent provided for in this Agreement or the Credit Documents or
in any of the other instruments or agreements securing the Obligations or now or
hereafter existing at law or in equity or by statute shall be cumulative and
concurrent and shall be in addition to every other such right, power or remedy.
The exercise or beginning of the exercise by the Administrative Agent of any one
or more of the rights, powers or remedies provided for in this Agreement, the
Credit Documents or in any such other instrument or agreement now or hereafter
existing at law or in equity or by statute or otherwise shall not preclude the
simultaneous or later exercise by the Administrative Agent of all such other
rights, powers or remedies, and no failure or delay on the part of the
Administrative Agent to exercise any such right, power or remedy shall operate
as a waiver thereof.

13. Continuing Agreement. This is a continuing agreement and shall remain in
full force and effect until terminated by written agreement of the parties and
until all of the principal of, premium, if any, and interest on all of the
Obligations have been fully paid. This Agreement and the liens and security
interests created and granted hereunder shall remain in effect, notwithstanding
the fact that at any time or from time to time there may be no Obligations
outstanding, in order to secure all future Obligations. If this Security
Agreement is revoked by operation of law as against the Grantor, the Grantor
will indemnify and save the Administrative Agent and its successors or assigns,
harmless from any loss which may be suffered or incurred by them in making,
giving, granting or extending any loans or other credit, financing or financial
accommodations, or otherwise acting, hereunder prior to receipt by the
Administrative Agent of notice in writing of such revocation.

14. Miscellaneous. This Agreement shall be governed by the laws of the State of
North Carolina in all respects, including matters of construction, validity and
performance except to the extent that the remedies provided herein with respect
to any of the collateral are governed by the laws of any jurisdiction other than
North Carolina; section headings herein are for the convenience of reference
only and shall not affect the construction or interpretation of or alter or
modify the provisions of this Agreement; none of the terms or provisions of this
Agreement may be waived, altered, modified, limited or amended except by an
agreement expressly referring hereto and to which the Administrative Agent
consents in writing duly signed for the Administrative Agent and on the
Administrative Agent’s behalf; the rights granted to the Administrative Agent
herein shall be supplementary and in addition to those granted to the
Administrative Agent and/or the Secured Parties in any Credit Documents; the
addresses of the parties for delivery of notices, requests, demands and other
communications hereunder are as set forth in the Credit Agreement. No reference
to “proceeds” in this Agreement authorizes any sale, transfer, or other
disposition of the Collateral by the Grantor.

15. Duties of Administrative Agent. The Administrative Agent has been appointed
by the Secured Parties pursuant to the Credit Agreement. Its duties to the
Secured Parties, powers to act on behalf of the Secured Parties, and immunity
are set forth solely therein, and shall not be altered by this Security
Agreement. Any amounts realized by the Administrative Agent hereunder shall be
allocated pursuant to the Credit Agreement.

[Remainder of page intentionally left blank]

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IN WITNESS WHEREOF, this Security Agreement has been executed as of the day and
year first above written.

GRANTOR:

MAIN STREET CAPITAL CORPORATION

By: /s/ Todd A. Reppert

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      Name:     Todd A. Reppert     Title: President             [CORPORATE
SEAL]

SCHEDULE I

Executive Office

The Executive Office of the Grantor is as follows:

11300 Post Oak Boulevard, Suite 800

Houston, TX 77056

Attention: Todd A. Reppert, President

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