BOSTON (AP) â¿¿ Shares of life insurance companies rallied to 52-week highs Friday as a surprisingly strong jobs report pushed bond yields to their highest levels in nearly a year. Insurance companies are major institutional investors in bonds, investing funds from policyholders' premium payments and using the proceeds to pay out future claims and generate profits. But the Federal Reserve's policy of keeping short-term interest rates near zero to stimulate the economy has sharply reduced bond yields in recent years, pressuring the ability of insurers to generate strong investment returns. However, the yield on benchmark 10-year Treasury bond climbed to its highest level in 11 months on Friday to 2.06 percent. The yield has risen from about 1.70 percent since the start of the year, and from 1.85 percent since March 1. The climb has been driven in part by optimism that hiring is picking up, bolstering the stock market. Higher stock prices encourage investors to move money out of conservative investments like bonds, pushing bond yields higher. And on Friday, the Labor Department added fuel to the fire with a February jobs report that showed the unemployment rate dropping to a four-year low. Shares of several life insurance companies outperformed the broader market on Friday, led by Met Life Inc. Its shares rose $1.82, or 4.9 percent, to close at $39.03. That's the stock's highest level in more than 11 months. Shares of Hartford Financial Services Group Inc. recorded a 52-week high, rising $1.10, or 4.5 percent, to $25.45. The stock's previous high was $25.37, reached Feb. 1. Also topping 52-week highs were Lincoln National Corp., whose shares rose $1.37, or 4.3 percent, to $33, and Principal Financial Group Inc., which added 77 cents, or 2.4 percent, to $33.42. Another strong performer was Prudential Financial Inc., which added $1.37, or 2.4 percent, to $59.60.