It was May 19, when the U.S. indicted five Chinese officials and put them on the Federal Bureau of Investigation’s most-wanted list for cyber crimes. After the move, China excluded Microsoft Corp.’s Windows 8 from a state purchasing order, asked banks to switch from International Business Machines Corp. (IBM) servers to a local brand and said it will vet technology firms for national-security breaches.

Speculation that the dispute will give China’s technology companies an advantage over U.S. rivals has turned the CSI 300 Information Technology Index into the best performer among 10 industry groups from the worst. Lenovo Group Ltd. (992), which agreed to buy IBM’s low-end server unit in January, jumped 9.9 percent in a seven-day rally through yesterday, its longest winning streak since 2003, while Yonyou Software Co. surged 28 percent.