July 22 (Bloomberg) -- Shin-Etsu Chemical Co., the world’s largest maker of silicon wafers for semiconductors, rose the most in more than three months in Tokyo trading after saying it aims to raise wafer prices for the first time in three years.

Shin-Etsu gained 4.9 percent to close at 4,740 yen on the Tokyo Stock Exchange, the sharpest increase since April 9 and the highest close since June 12. Sumco Corp., the world’s second-largest maker of silicon wafers, gained 4.6 percent to 1,579 yen, the highest since May 8.

The Nikkei newspaper reported earlier that Shin-Etsu is in talks with customers to raise the price of 300-millimeter wafers by as much as 40 percent. Tetsuya Koishikawa, a spokesman at Tokyo-based Shin-Etsu, declined to comment on the extent of the price increase the company is seeking.

“The move is understandable if it’s a pre-emptive act ahead of next year, though it might be difficult for chipmakers to accept it right away,” Takeo Miyamoto, a Tokyo-based chip- industry analyst at Deutsche Bank AG, said in a phone interview.

There is little room for makers of dynamic random access memory, or DRAM, to accept such requests, Miyamoto said. Makers of flash memory chips used in mobile phones and portable music players may have room to consider increases, he said.

Spot prices of the benchmark computer-memory chip gained 8 percent in the three months ended June 30, after reaching a record low in December, according to Dramexchange Technology Inc., the operator of Asia’s biggest spot market for semiconductors.

Shin-Etsu’s gain made it the sixth-best performer on Japan’s Nikkei 225 Stock Average today.

To contact the reporter on this story: Norie Kuboyama in Tokyo at nkuboyama@bloomberg.net

Last Updated: July 22, 2009 03:23 EDT