Southwest Bancorp (OKSB), a bank holding company with offices in Oklahoma, Texas and Kansas, said Thursday its chief financial officer will leave the company in late June.

Laura Robertson, also an executive vice president, resigned from the company after 18 months, according to a news release. Southwest did not provide a reason for her resignation.

“She assumed the position of chief financial officer at a very difficult time for Southwest, and her dedication and guidance have been invaluable,” President and CEO Rick Green said in the release. “We wish her well in her future endeavors.”

Southwest said Randy Waldrup will join the company June 4 to serve as interim CFO. 

The company also said it plans to resume dividend payments on securities, including a deferred dividend worth $7.4 million for the Treasury Department.