White Mountains Solutions, a subsidiary of White Mountains Insurance Group, is acquiring Physicians Insurance of Ohio and Citation Insurance Company from PICO Holdings.
Both companies ceased underwriting in the mid-1990's and have been in runoff ever since.
White Mountains Solutions has agreed to pay around $17 million, subject to certain targeted pre-closing dividends.
"This acquisition continues our long track record of success in completing runoff acquisitions that allow sellers to achieve a clean exit from the insurance business," said Neal Wasserman, president of White Mountains Solutions.