Elpida will buy 94.3 million shares of Rexchip Electronics by the end of March to increase its stake in Rexchip to 52 percent from 48.8 percent currently.
Elpida and Powerchip said the price of the shares has not yet been determined.
Rexchip is a private venture owned by Powerchip and Elpida. The two companies teamed up in late 2006 to start developing Rexchip. The partnership involves sharing the costs of building advanced DRAM chip factories, which can cost around US$3 billion each, and joint development of chip technology.
Powerchip is the largest memory chip maker in Taiwan, but a DRAM market downturn has hit it hard financially. The company has reported net losses totaling NT$32.03 billion (US$963.6 million) for the first nine months of this year, has announced a hiring freeze and said it won't build any new production lines next year.
A glut of DRAM chips caused prices to tumble late last year, turning most DRAM makers into money losers. DRAM chip prices remain low, dropping to new record lows week by week.