Greenlight Capital, David Einhorn's hedge fund firm, gained 7.9 percent in the second quarter, according to a letter sent to investors Friday.
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."
A spokesman for Greenlight declined to comment.
The largest long positions for Greenlight as of June 30 were Apple, gold, Marvell Technology, Micron Technology, Resona Holdings and SunEdison. Short positions, which cost the fund in the second quarter, were not fully listed.
On Micron, the letter said that "we believe consensus earnings estimates remain too low, positioning the company for further earnings surprises and multiple expansion."
On Apple, Greenlight noted that "AAPL remains inexpensive at about 11x earnings net of cash."
The contents of the letter were previously reported by MarketFolly.
—By CNBC's Lawrence Delevingne