PORTLAND – Anthem plans to eliminate more than 270 jobs in Portland before next March, the company said.

The cuts stem from a client’s decision to stop using Maine workers to process claims. The contract loss has prompted Anthem to close a small case management office and to shuffle workers between a Portland office and its headquarters in South Portland.

Affected workers can apply for other jobs within the company, said Anthem spokesman Bill Cohen. He said it was too soon to know how many people would be laid off.

“We made a conscious decision to let people know way up front,” Cohen said. “We hope to get as much of this as we can through attrition.”

Anthem, the state’s largest health insurer, has 1,550 employees in Maine.

Seven years ago, Blue Cross and Blue Shield of Maine entered into an agreement to process medical claims forms for Blue Cross and Blue Shield of Minnesota.

The operation began with 150 workers in 1996 and grew to 277 today. It remained in place after Anthem bought Maine Blue Cross in 2000.