An Ohio-based health insurance company is pulling out of South Carolina at the end of 2013, leaving 28,000 beneficiaries wondering who will insure them on Jan. 1.

Ed Byers, a spokesman for Medical Mutual, which manages the Carolina Care health insurance plans in South Carolina, confirmed the company is exiting this market and is “working closely with UnitedHealthcare to transition all of the affected policyholders.”

A letter dated June 2013 explained to Medical Mutual customers that the company intends to “focus on its core business in Ohio.” It is also dropping customers in Georgia and Indiana, Byers confirmed.

He said new regulations under the federal Patient Protection and Affordable Care Act haved forced the company to retreat from South Carolina, but declined to say which regulations specifically dictated this decision.

“Without getting into the specifics, which are vast, it takes a great deal of resources and effort to comply with reform,” Byers said. “New regulations put us in a position of focusing our efforts and spending our resources on our core Ohio business. It is critical for the company to do well in Ohio.”

Medical Mutual is the second-largest health insurer for individual plans in South Carolina, according to 2011 data compiled by the Kaiser Family Foundation. Blue Cross Blue Shield of South Carolina dominates the health insurance market in the state.

Reach Lauren Sausser at 937-5598.