Southwest Bancorp (OKSB) 8-K/A Changes in Registrant's Certifying Accountant

EXHIBIT 16.1 TO FORM 8-K

March 10, 2015

Securities and Exchange Commission
100 F Street, N.E.
Washington, DC 20549

Ladies and Gentlemen:

We have read Item 4.01 of Form 8-K dated March 10, 2015, of Southwest Bancorp, Inc. and are in agreement with the statements contained in the paragraphs 1,  2, and 4  listed under “Change in Registrant’s Certifying Accountant” on page 2 therein. We have no basis to agree or disagree with other statements of the registrant contained therein.

/s/ Ernst & Young LLP