White Mountains Re Ltd. is going to acquire Central National Insurance Co. of Omaha from Drum Financial Corp., the sixth runoff acquisition for the company.

New York-based White Mountains, a wholly owned subsidiary of White Mountains Insurance Group, will pay about $5 million for the company, which has been in runoff since 1989. Central National has been operated under an order of rehabilitation by Nebraska regulators since 1990.

The acquisition will require the approval of the Nebraska Department of Insurance and the court overseeing the rehabilitation. Central National, based in Omaha, Neb., had a statutory surplus of $13.3 million, as of Sept. 30, 2009.

“We are very pleased by the terms of this transaction put together by the White Mountains Re Solutions team,” said Allan Waters, president and CEO of White Mountains Re, in a statement. “Although modest in size, this transaction continues our long history of building shareholder value through acquisitions of runoff insurance and reinsurance companies.”

Neal Wasserman, president of White Mountains Re Solutions said: “Despite a competitive market the past few years in the runoff sector, this acquisition demonstrates our ability to successfully complete value-adding acquisitions that meet our return thresholds while at the same time allowing sellers to achieve their goal of extracting trapped capital and obtaining a full and final exit from the insurance business.”

White Mountains Re expects the transaction to close during the first quarter of 2010 subject to regulatory approvals and other customary closing conditions.

White Mountains Re Ltd. is a wholly owned subsidiary of White Mountains Insurance Group, a Bermuda-domiciled financial services holding company.