NAPA -- The Doctors Company, the largest medical malpractice insurer in the country, said it signed a merger agreement with the Utah Medical Insurance Association.

The deal to acquire the association through its wholly owned subsidiary, Underwriter for the Professions Insurance Company, would broaden the Napa-based insurer's coverage area to Utah, Montana and Wyoming. Financial terms of the deal were not disclosed.

The 3,000 additional physician policyholders would bring The Doctors Company's total to more than 76,000. Upon completion of the merger, Underwriter for the Professions would become UMIA Insurance Company, a Member of the TDC Group of Companies.

"The combined organization will provide UMIA policyholders with the financial strength of a physician-owned insurer with multiple 'A' ratings and a commitment to relentlessly defend, protect, and reward its members," said Richard Anderson, M.D., FACP, chairman and chief executive officer of The Doctors Company, in a statement.

The UMIA Board of Governors unanimously approved and recommended the merger. The deal is expected to close before the end of the first quarter in 2013, pending approvals by regulators and a majority of UMIA’s subscribers.

“We believe the partnership between UMIA and The Doctors Company will provide significant value to our physician policyholders,” said Martin J. Oslowski, UMIA’s president and CEO, in a statement. "Both organizations share a common mission of providing outstanding service to our members, and this synergy was an important factor as we decided to enter into the agreement.”

UMIA is an Oregon reciprocal insurance company with headquarters in Salt Lake City. It has provided medical professional liability insurance for physicians, clinics, and hospitals since it was founded in 1978. As a result of the merger, the purchase price will be paid to UMIA’s subscribers, and their coverage will continue with UMIA Insurance.

The merger is the third acquisition for The Doctors Company in just less then three years. In 2010, the insurer acquired Michigan-based American Physicians Capital Inc., for $41.50 per share in cash, or approximately $386 million. In 2011, The Doctors Company acquired Florida-based FPIC Insurance Group, then a major publicly traded medical liability insurer throughout the Southeast, for about $362 million.