Exhibit 99.1

AMENDMENT NO. 2

to

AGREEMENT AND PLAN OF REORGANIZATION

This Amendment No. 2 (this “Amendment”) dated June 30, 2015 to the Agreement and Plan of Reorganization dated January 8, 2014, as amended July 21, 2014 (the “Agreement”), is by and between BancorpSouth, Inc., a corporation organized and existing under the laws of Mississippi (“BancorpSouth”), and Ouachita Bancshares Corp., a corporation organized and existing under the laws of Louisiana (the “Company”). Capitalized terms used but not defined in this Amendment shall have the meaning ascribed to such terms in the Agreement.

WHEREAS, BancorpSouth and the Company have heretofore entered into the Agreement, which provides for, among other things, the merger of the Company with and into BancorpSouth, with BancorpSouth surviving (the “Merger”), upon the terms and conditions set forth therein; and

WHEREAS, BancorpSouth and the Company desire to amend the Agreement in accordance with Section 13.4 thereof as provided below;

NOW, THEREFORE, in consideration of the mutual agreements set forth in the Agreement and this Amendment, and for other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, BancorpSouth and the Company hereby agree as follows:

1. Amendment of Agreement.

(a) Pricing Floor. The Agreement is hereby amended by replacing:

“$23.04” in Section 2.3(c)(i) with “$24.00”;

“$18.43” in Sections 2.3(c)(i) and (ii) with “$19.20”;

“107,547,000” in Section 2.3(c)(i) with “$111,075,000”; and

“39,809,400” in Section 2.3(c)(ii) with “$40,515,000”.

(b) Extension. The Agreement is hereby amended by deleting Section 9.1(a)(iii) thereof in its entirety and replacing it with the following:

“(iii) the Effective Time has not occurred on or before December 31, 2015, or such later date as has been approved in writing by the Boards of Directors of BancorpSouth and the Company; but the right to terminate under this Section 9.1(a)(iii) shall not be available to any party whose failure to fulfill any material obligation under this Agreement has been the cause of, or has resulted in, the failure of the Effective Time to occur on or before such applicable date;”

2. Material Adverse Effect. For the purpose of measuring whether a Material Adverse Effect has occurred under the Agreement, the relevant effects, changes, developments or occurrences shall be those effects, changes, developments or occurrences existing on, and that

have been disclosed as of, the date of this Amendment, not the date of the Agreement; provided, however, that no effect, change, development or occurrence relating to the financial condition, assets, properties, deposits, results of operations, earnings, business or cash flows of the Company resulting primarily from the delays associated with the completion of the transactions contemplated by the Agreement shall be deemed to constitute a Material Adverse Effect with respect to the Company.

3. References. Each reference in the Agreement to “this Agreement,” “hereof,” “hereunder” or words of like import referring to the Agreement shall mean and be a reference to the Agreement as amended by this Amendment.

4. Effect of Amendment. This Amendment shall not constitute an amendment or waiver of any provision of the Agreement not expressly amended and or waived herein and shall not be construed as an amendment, waiver or consent to any action that would require an amendment, waiver or consent except as expressly stated herein. The Agreement, as amended by this Amendment, is and shall continue to be in full force and effect and is in all respects ratified and confirmed hereby.

5. Controlling Law. This Agreement and any claim, controversy or dispute arising under or related in any way to this Agreement and/or the interpretation and enforcement of the rights and duties of the parties hereunder or related in any way to the foregoing, shall be governed by and construed in accordance with the internal, substantive laws of Mississippi applicable to agreements entered into and to be performed solely within such state without giving effect to the principles of conflict of laws thereof.

6. Counterparts. This Agreement may be executed in multiple counterparts (including by means of telecopied signature pages or electronic transmission in portable document format (pdf)), any one of which need not contain the signatures of more than one party, but all such counterparts taken together shall constitute one and the same instrument.

[Signature Page Immediately Follows]

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IN WITNESS WHEREOF, the parties have caused this Amendment to be executed as of the date first above written.

[Signature Page to Amendment No. 2 to the Agreement and Plan of Reorganization]