David Tepper, billionaire founder of Appaloosa Management, said Friday he still likes this bull market, which is the longest on record.
"I love riding a horse that's running," Tepper told CNBC's Joe Kernen in an exclusive email. "We have been long and continue that way."
The current bull market started in March 2009. Since then, the S&P 500 has skyrocketed more than 380%. On Thursday, the S&P 500 reached an all-time high and broke above 3,300 for the first time.
The hedge fund billionaire made a bold call on CNBC back in 2010, betting on the power of the Federal Reserve's easing program. Tepper predicted then that super-low interest rates and the central bank's massive bond buying would make most investment choices go up. His market advice turned out to be spot-on for the whole decade.
However, there are signs the bull market may be a bit long in the tooth. The U.S. equity market cap-to-GDP ratio — a measure of how big the stock market is relative to the broader economy — recently hit an all-time high. The cyclically adjusted price-to-earnings (CAPE) ratio — which was created by Nobel Prize winner Robert Shiller — currently sits near its dot-com bubble high.
Tepper told Kernen that "at some point, the market will get to a level that I will slow down that horse and eventually get off." He did not, however, specify when that would be.
—CNBC's Yun Li contributed to this report.