Lincoln National Corp. led a slump among shares of life insurers Wednesday after the Federal Reserve said it will expand its Operation Twist program to reduce longer-term interest rates.

Lincoln, the insurer that repaid a $950 million U.S. bailout, fell 2.1 percent to $21.26 at 3:11 p.m. in New York. MetLife Inc., the largest U.S. life insurer, reversed gains after the Fed announcement, sliding 22 cents to $30.66.

The central bank will expand its program to replace short- term bonds with longer-term debt by $267 billion through the end of the year in a bid to lower unemployment and protect the economic expansion, according to a statement today. The program will “put downward pressure” on interest rates of longer-term debt, the Federal Open Market Committee said in the statement.

“Life insurers are adversely affected by low interest rates, in part, because of lower returns on their investments and previous guarantees promised to the policyholders,” John Fenton, senior life insurance consultant at Towers Watson & Co., said in an e-mailed statement before the Fed announcement.

MetLife has slipped 1.7 percent this year. Radnor, Pennsylvania-based Lincoln advanced 9.5 percent.