Jeffrey Gundlach, the co-founder and chief executive officer of DoubleLine Capital, said on Friday that his firm purchased some U.S. stocks two weeks ago after their rocky start in January.

"I thought it was a good buy point two weeks ago Wednesday and so we bought some," Gundlach told Reuters. Gundlach, who oversees $90 billion in assets for the Los Angeles-based DoubleLine, said the firm was at "maximum underweight" since last August.

He also said oil will "really easily" rally toward $40 a barrel as the price has dropped so much. Last year, Gundlach correctly predicted that oil prices would plunge, junk bonds would live up to their name and China's slowing economy would pressure emerging markets.

In 2014, Gundlach also correctly forecast U.S. Treasury yields would fall, not rise as many others had expected.

Gundlach said the Shanghai Composite, which is trading around 2,767 points, is set to fall to around 2,500.