NEW YORK (Bloomberg) — Bonds of US insurance companies were lowered to “market weight” by Lehman Brothers Holdings Inc. after the securities outperformed the firm’s investment-grade credit index since June.

Lehman cut its recommendation for life insurance companies from “modest overweight,” and lowered its call on property and casualty insurers from “strong overweight, the firm said in a research report dated December 1.

The extra yield, or spread, on bonds of life insurers above similar-maturity Treasuries has narrowed 15 basis points, or 0.15 percentage point, since June, according to data compiled by Lehman. By contrast, the average spread on investment-grade bonds has narrowed 7 basis points, while the premium for financial institutions has shrunk 11 basis points, according to the report.

“We think it makes sense to take profits in the insurance sectors, which have enjoyed an extraordinary run in the past few months,” Lehman analysts wrote. “There is little room for further outperformance.”

Lehman analyst Tom Walsh still remains “constructive” on the fundamentals of the insurance industry because property and casualty insurers have benefited from a benign hurricane season, according to the report.