KLA-Tencor Shares Rise on S&P; 500 Inclusion

KLA-Tencor Corp. shares rose 4% after Standard & Poor’s said it will add the company to the S&P; 500 index. KLA-Tencor, which makes products used in the manufacture of computer chips, will replace Amdahl Corp. on the index after the close of trading Friday, S&P; said. Managers of mutual funds that mimic the makeup of the index buy shares of the new companies in the index to keep their holdings consistent, often causing those stocks to rise. San Jose-based KLA-Tencor, formerly KLA Instruments Corp., was formed through KLA’s $1.38-billion stock purchase of Tencor Instruments in April. Amdahl, based in Sunnyvale, is being replaced because Fujitsu Ltd., a Japanese company that already owns 42% of Amdahl, is acquiring the rest of it in a tender offer set to expire at that time. Amdahl shares fell 6 cents to close at $12.31 in American Stock Exchange trading. Shares in KLA-Tencor rose $2.81 to close at $72.69 on Nasdaq.