Greenlight takes Lam Research stake, gains on Micron, Apple
Greenlight Capital, David Einhorn's hedge fund firm, gained 7.9 percent in the second quarter, according to a letter sent to investors Friday.

The fund gained on Micron Technology , Apple , SunEdison , Altice , Resona and Civeo , according to the letter, bringing returns for the first half of 2014 to 6.4 percent net of fees.

Greenlight also disclosed that it made a "medium sized" new investment in Lam Research , which makes semiconductor capital equipment.

"As transistors get smaller and smaller, the conversion of semiconductor designs into working chips becomes more difficult," the letter said. "The solution, known as 'multi-patterning', involves running each layer of the chip through the manufacturing line multiple times, etching away the excess material until the chip works properly. This forces chip manufacturers to buy more of LRCX's etchers and deposition tools for each manufacturing line."