OMEGA: 'It is time for the US equity market to rest'

Lee Cooperman's Omega Advisors expects the rampant bull market to slow down.

"It is time for the U.S. equity market to rest," Cooperman and Steve Einhorn, Omega's vice chairman, wrote in a letter to investors last week. A copy of the note was reviewed by Business Insider.

The 56-page letter continued:

"Notwithstanding our expectation that the in-place U.S. equity bull market should persist, for the first time in quite some time, we are of the view that U.S. shares should be trendless/uninteresting at around current levels for a number of months...we would not be surprised if the S&P500 was at roughly the same level in late summer/early fall as it is currently."

Omega was up 6.5% in the first quarter, according to the letter. The returns before and after fees were listed as the same.

Last year, the Securities and Exchange Commission charged Omega and Cooperman with insider trading. Cooperman has said he is innocent and that he will fight the charges.