Briefly

AMN Healthcare Services Inc. of San Diego, the biggest U.S. provider of temporary nurses to hospitals, filed Monday for an initial public offering estimated to raise as much as $172.5 million. AMN, which said it plans to use money raised through the IPO to repay debt, plans to list the shares on the New York Stock Exchange under the symbol AHS. . . . The credit rating of Calpine Corp. (CPN) may get a boost and bonds from other power generators may extend gains after a court ruling buoyed the outlook for power sellers to be paid for electricity sold to California utilities. A Bankruptcy Court judge last week affirmed Calpine’s agreement with bankrupt Pacific Gas & Electric Co., the state’s No. 1 utility, to receive payment for past power sales.