Oct. 14 (Bloomberg) -- Elpida Memory Inc., Japan’s biggest computer memory-chip maker, said it may raise stake in its venture with Taiwan’s Powerchip Semiconductor Corp. to more than 70 percent by Dec. 31.

The Tokyo-based company yesterday increased its holding in Rexchip Electronics Corp. to 64 percent, from 52 percent, Elpida’s spokesman Hiroshi Tsuboi said by telephone today. Powerchip gave Elpida 350 million shares worth more than 10 billion yen ($111 million) to repay an earlier loan from the Japanese chipmaker, lowering its stake to about 34 percent, Tsuboi said.

Elpida is strengthening its ownership of the Taichung, Taiwan-based venture to secure chip supply as improving demand bolsters prices of the devices. Rexchip became profitable on an operating basis in August, helped by the rising prices and a switch to production of smaller, more cost-efficient chips, Elpida said last week.

The Japanese company plans to increase its stake in Rexchip to 71 percent by the end of the year, Nikkei English News reported earlier, without citing anyone.

The price of benchmark dynamic random access memory, which temporarily holds data and helps computer processors run multiple programs simultaneously, more than tripled this year, according to Dramexchange Technology Inc., operator of Asia’s biggest spot market for semiconductors. The price slumped 62 percent in 2008.

Elpida rose 2.9 percent to 1,255 yen as of 9:12 a.m. on the Tokyo Stock Exchange, compared with a 0.2 percent decline by the benchmark Nikkei 225 Stock Average. Powerchip fell 0.6 percent in Taipei trading yesterday.

Profitability at Rexchip was helped by a switch to 65- nanometer chip production, from 70-nanometer, Elpida said last week. A nanometer is a billionth of a meter and measures the width of transistors in a chip, where a smaller gap means more transistors can be packed on each wafer, making the chip cheaper to make.

To contact the reporter on this story: Pavel Alpeyev in Tokyo at palpeyev@bloomberg.net.

Last Updated: October 13, 2009 20:20 EDT