Mortgage insurers rallied Friday on an Obama administration plan to expand a multibillion dollar mortgage-modification program to help jobless homeowners. Shares of PMI Group Inc. rose 8.6% to $4.53, Radian Group shares grew 9% to $14.27, MGIC Investment Corp. shares increased 6.8% to $9.53, and Genworth Financial Inc. shares advanced 3.6% to $17.49 in recent trading.