Exhibit 99

Southwest Bancorp, Inc. Reports Net Income

of $5.9 Million for the Third Quarter of 2012

October 18, 2012, Stillwater, Oklahoma . . . . Southwest Bancorp, Inc. (NASDAQ Global Select Market—OKSB, OKSBP), (“Southwest”), today reported earnings for the third quarter of 2012 of $5.9 million, compared to a loss of ($9.5) million for the third quarter of 2011. Net income available to common shareholders was $4.3 million, or $0.22 per diluted share for the third quarter of 2012, compared to a net loss available to common shareholders of ($10.6) million, or ($0.54) per diluted share for the third quarter of 2011.

Southwest reported earnings for the nine months ended September 30, 2012 of $15.2 million, compared to a loss of ($10.0) million for the nine months ended September 30, 2011. Net income available to common shareholders for the nine months ended September 30, 2012 totaled $11.5 million or $0.59 per diluted share compared to a net loss available to common shareholders of ($13.2) million or ($0.68) per diluted share for the nine months ended September 30, 2011.

Rick Green, President Emeritus, stated, “During the third quarter, Southwest took actions to achieve its strategic goals. In July, we resumed payment of dividends on the three trust preferred securities and our Series B Preferred securities and brought current all dividends that had been previously deferred. The Series B Preferred securities were issued by Southwest to the U.S. Treasury Department under the Treasury’s Capital Purchase Program in December 2008.”

“In August 2012, Southwest completed the repurchase of all $70.0 million of the Series B Preferred securities sold to the Treasury. Southwest incurred a one-time non-cash equity charge of $1.2 million to reflect accelerated accretion of the remaining discount on the securities. The funds for the repurchase were internally generated, and Southwest and each of its banking subsidiaries remain well capitalized after the repurchase.”

“We were able to accomplish these goals while at the same time improving year-to-date profitability, stabilizing asset quality, and maintaining strong capital levels.”

Mr. Green went on to say, “As previously announced, on October 1, 2012 Mark W. Funke became Southwest’s President and Chief Executive Officer. Mr. Funke previously served as market president for Bank of Oklahoma – Oklahoma City.”

“These actions are designed to allow Southwest to continue to pursue our strategy of independent operation for the benefit of all of our shareholders.”

Mark Funke, new President and Chief Executive Officer, stated “I am excited to join this organization and expect to lead Southwest on a path of conservative growth. We will continue to have an emphasis on solid underwriting and taking advantage of opportunities for growth and increasing shareholder value.”

Key items for the quarter were as follows:

Unless otherwise indicated, the following discussion excludes “covered” assets, which are subject to loss sharing agreements with the FDIC. For information on covered versus noncovered assets, please see the accompanying unaudited financial statement and tables.

NASDAQ: OKSB   

OKSBP

Southwest Bancorp, Inc. Reports Net Income of $5.9 Million for the Third Quarter of 2012

Financial Overview

Condition: At September 30, 2012 total assets were $2.2 billion, down $226.1 million, or 9%, from December 31, 2011, and total loans were $1.5 billion, down $271.4 million, or 15%, from December 31, 2011.

At September 30, 2012 the noncovered allowance for loan losses was $43.6 million, a decrease of 1% from December 31, 2011. The noncovered allowance for loan losses to noncovered portfolio loans was 3.05% as of September 30, 2012 compared to 2.62% as of December 31, 2011.

Investment securities increased $106.1 million, or 39%, to $381.5 million as of September 30, 2012, from $275.4 million as of December 31, 2011. The increase is primarily the result of a $53.7 million, or 82%, increase in U.S. government and agency securities, a $29.4 million, or 16%, increase in government agency guaranteed residential mortgage-backed securities, a $21.3 million, or 81%, increase in municipal securities, and a $1.2 million increase in other mortgage-backed securities. The investment portfolio is managed to provide safety, liquidity, and collateral for public funds and borrowings. Southwest plans to continue to invest in treasury, U.S. agency, and high grade municipal securities. The investment portfolio continues to be managed in compliance with the current investment policy, including interest rate and liquidity risk stress testing, and the average duration of the portfolio not exceeding four years.

NASDAQ: OKSB   

OKSBP

Southwest Bancorp, Inc. Reports Net Income of $5.9 Million for the Third Quarter of 2012

Total core funding, which includes all non-brokered deposits and sweep repurchase agreements, comprised 98% of total funding as of September 30, 2012, compared to 94% at December 31, 2011. Core funding by segment is as follows as of September 30, 2012 and December 31, 2011, respectively: $1,335.2 million and $1,426.2 million in Oklahoma banking, $162.8 million and $156.2 million in Texas banking, $263.9 million and $273.6 million in Kansas banking, and $8.9 million and $3.9 million in the secondary market and other operations segments. Wholesale funding, including FHLB borrowings, federal funds purchased, and brokered deposits, accounted for 2% of total funding at September 30, 2012, compared to 6% at December 31, 2011. Please see Table 7 for details on these non-GAAP financial measures.

Third Quarter Results:

Summary: For the third quarter of 2012, net income available to common shareholders was $4.3 million, compared to a net loss available to common shareholders of ($10.6) million for the third quarter of 2011. The $14.9 million increase in our net income available to common shareholders from third quarter 2011 is the result of a $26.4 million decrease in the provision for loan losses, a $3.1 million decrease in noninterest expense, and a $0.4 million increase in noninterest income, offset in part by a $5.3 million decrease in net interest income and a $9.1 million increase in income tax expense.

The third quarter 2012 effective tax rate was 39.73%.

Net Interest Income: Net interest income totaled $18.7 million for the third quarter of 2012, compared to $24.0 million for the third quarter of 2011, a decrease of $5.3 million, or 22%, and to $19.7 million for the second quarter of 2012, a decrease of $1.1 million, or 5%. Lower average loan volume was the primary cause of each of these decreases. Net interest margin was 3.59% for the third quarter of 2012, compared to 3.77% for the third quarter of 2011 and 3.71% for the second quarter of 2012.

Provision for Loan Losses and Net Charge-offs: A negative provision for loan losses of $1.7 million was recorded for the third quarter of 2012, compared to a provision for loan losses of $24.6 million for third quarter of 2011 and $32,000 for the second quarter of 2012. For the third quarter of 2012, net recoveries totaled $1.6 million, or (0.42%) (annualized) of average portfolio loans, compared to net charge-offs of $14.5 million, or 2.70% (annualized) of average portfolio loans for the third quarter of 2011 and $1.2 million, or 0.31% (annualized) of average portfolio loans for the second quarter of 2012. The provision for loan losses is the amount that is required to maintain the allowance for losses at an appropriate level based upon the inherent risks in the loan portfolio after the effects of net charge-offs or net recoveries for the period.

Noninterest Income: Noninterest income totaled $4.0 million for the third quarter of 2012, compared to $3.6 million for the third quarter of 2011 and $3.6 million for the second quarter of 2012. The increase in noninterest income is the result of increased gains on sale of mortgage loans.

Noninterest Expense: Noninterest expense totaled $14.6 million for the third quarter of 2012, compared to $17.7 million for the third quarter of 2011 and $16.8 million for the second quarter of 2012.

The $3.1 million decrease from third quarter of 2011 consists of a $1.9 million decrease in general and administrative expense, which is primarily the result of decreased loan collection costs and legal fees, a $0.4 million decrease in personnel expense, a $0.4 million decrease in the provision for unfunded loan commitments, a $0.3 million decrease in FDIC and other insurance expense, and a $0.2 million decrease in other real estate expense.

The $2.2 million decrease from second quarter of 2012 consists of a $0.8 million decrease in other real estate expense due to the second quarter fair value write-down of properties, a $0.8 million decrease in general and administrative expense, which is primarily the result of decreased legal fees, decreased loan review costs and the second quarter write-down of an investment carried at cost, and a $0.5 million decrease in the provision for unfunded loan commitments.

Year-to-date Results:

Summary: Net income available to common shareholders was $11.5 million as of September 30, 2012, compared to a net loss available to common shareholders of ($13.2) million as of September 30, 2011. The $24.7 million increase in our net income available to common shareholders from 2011 is the result of a $53.8 million

NASDAQ: OKSB   

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Southwest Bancorp, Inc. Reports Net Income of $5.9 Million for the Third Quarter of 2012

decrease in the provision for loan losses, a $2.6 million decrease in noninterest expense, and a $0.6 million increase in noninterest income, offset in part by a $15.2 million decrease in net interest income and a $16.6 million increase in income tax expense.

The year-to-date effective tax rate was 38.28% as of September 30, 2012.

Net Interest Income: Net interest income totaled $59.3 million for the first nine months of 2012, compared to $74.4 million for the first nine months of 2011, a decrease of $15.2 million, or 20%. Lower loan volume was the primary cause of this decrease. Year-to-date net interest margin was 3.71%, compared to 3.78% for 2011.

Provision for Loan Losses and Net Charge-offs: The provision for loan losses totaled $22,000 for the first nine months of 2012, compared to $53.8 million for the first nine months of 2011. Net charge-offs totaled $1.0 million, or 0.08% (annualized) of average portfolio loans year-to-date as of September 30, 2012, compared to $54.3 million, or 3.24% (annualized) of average portfolio loans for the same period 2011. The provision for loan losses is the amount that is required to maintain the allowance for losses at an appropriate level based upon the inherent risks in the loan portfolio after the effects of net charge-offs for the period.

Noninterest Income: Noninterest income totaled $11.1 million for the first nine months of 2012, compared to $10.4 million for the first nine months of 2011. The increase in noninterest income was primarily the result of a $1.2 million increase in gain on sale of loans, offset in part by a $0.6 million decline in service charges and fees.

Noninterest Expense: Noninterest expense totaled $45.7 million for the first nine months of 2012, compared to $48.3 million for the first nine months of 2011. The decrease consists of a $1.0 million decrease in FDIC and other insurance expense, a $0.8 million decrease in other real estate expense, a $0.3 million decrease in personnel expense, a $0.3 million decrease in general and administrative expense, and a $0.3 million decrease in occupancy expense.

Southwest Bancorp and Subsidiaries

Southwest is the bank holding company for Stillwater National Bank and Trust Company (“Stillwater National”) and Bank of Kansas. Through its subsidiaries, Southwest offers commercial and consumer lending, deposit and investment services, specialized cash management, and other financial services from offices in Oklahoma, Texas, and Kansas, and on the Internet, through SNB DirectBanker®. We were organized in 1981 as the holding company for Stillwater National, which was chartered in 1894. At September 30, 2012 we had total assets of $2.2 billion, deposits of $1.7 billion, and shareholders’ equity of $250.4 million.

Our area of expertise focuses on the special financial needs of healthcare and health professionals, businesses and their managers and owners, and commercial and commercial real estate borrowers. We established a strategic focus on healthcare lending in 1974. We provide credit and other services, such as deposits, cash management, and document imaging for physicians and other healthcare practitioners to start or develop their practices and finance the development and purchase of medical offices, clinics, surgical care centers, hospitals, and similar facilities. As of September 30, 2012, approximately $521.0 million, or 36%, of our noncovered loans were loans to individuals and businesses in the healthcare industry. We conduct regular market reviews of our current and potential healthcare lending and the appropriate concentrations within healthcare based upon economic and regulatory conditions.

We also focus on commercial real estate mortgage and construction credits. We do not focus on one-to-four family residential development loans or “spec” residential property credits. Additionally, subprime residential lending has never been a part of our business strategy, and our exposure to subprime mortgage loans and subprime lenders is minimal. One-to-four family mortgages account for 5% of total noncovered loans. As of September 30, 2012 approximately $1.1 billion, or 75%, of our noncovered loans were commercial real estate mortgage and construction loans, including $353.4 million of loans to individuals and businesses in the healthcare industry.

Southwest’s common stock is traded on the NASDAQ Global Select Market under the symbol OKSB. Southwest’s public trust preferred securities are traded on the NASDAQ Global Select Market under the symbol OKSBP.

Caution About Forward-Looking Statements

We make forward-looking statements in this news release that are subject to risks and uncertainties. We intend these statements to be covered by the safe harbor provision for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995.

NASDAQ: OKSB   

OKSBP

Southwest Bancorp, Inc. Reports Net Income of $5.9 Million for the Third Quarter of 2012

These forward-looking statements include:

These forward-looking statements are subject to significant uncertainties because they are based upon: the amount and timing of future changes in interest rates, market behavior, and other economic conditions; future laws, regulations, and accounting principles; changes in regulatory standards and examination policies, and a variety of other matters. These other matters include, among other things, the direct and indirect effects of economic conditions on interest rates, credit quality, loan demand, liquidity, and monetary and supervisory policies of banking regulators. Because of these uncertainties, the actual future results may be materially different from the results indicated by these forward-looking statements. In addition, Southwest’s past growth and performance do not necessarily indicate our future results. For other factors, risks, and uncertainties that could cause actual results to differ materially from estimates and projections contained in forward-looking statements, please read the “Risk Factors” contained in Southwest’s reports to the Securities and Exchange Commission.

The cautionary statements in this release also identify important factors and possible events that involve risk and uncertainties that could cause our actual results to differ materially from those contained in the forward-looking statements. These forward-looking statements speak only as of the date on which the statements were made. We do not intend, and undertake no obligation, to update or revise any forward-looking statements contained in this release, whether as a result of differences in actual results, changes in assumptions, or changes in other factors affecting such statements, except as required by law.

Southwest is required under generally accepted accounting principles to evaluate subsequent events and their impact, if any, on its financial statements as of September 30, 2012 through the date its financial statements are filed with the Securities and Exchange Commission. The September 30, 2012 financial statements included in this release will be adjusted if necessary to properly reflect the impact of subsequent events on estimates used to prepare those statements.

NASDAQ: OKSB   

OKSBP

Southwest Bancorp, Inc. Reports Net Income of $5.9 Million for the Third Quarter of 2012

Financial Tables

Balance sheet amounts and ratios are as of period end unless otherwise noted.

Please see accompanying tables for additional financial information.