Billionaire hedge fund manager David Tepper sounded a cautious message on Wednesday, telling a ballroom packed with other managers and investors that he was "nervous" about the stock market but that this was not the time to sell.

Billed as the star attraction at the $2.7 trillion industry's biggest annual event, Tepper discussed economic growth, central bank policies as well as his personal commitment to supporting local soup kitchens and food banks in his adopted home state.

But his take on investing in U.S. markets got the most attention when he said: "I'm not saying go short, just don't be too friggin' long."

Coming from the man who earned $3.5 billion to rank as the hedge fund industry's best paid manager in 2013, this was exactly the kind of practical advice the roughly 1,800 attendees, some of whom jetted to Vegas on private planes, came to hear at the annual SkyBridge Alternatives Conference.

Tepper, who runs $20 billion Appaloosa Management, said he doesn't think U.S. economic growth is as strong as it should be and added that central banks are currently being complacent, noting that Europe's central bank "is behind the curve."

Even as the U.S. stock market hit records earlier this week, he worried that it was struggling to move significantly higher now after having surged roughly 30 percent last year.

He wasn't the only one debating what central banks around the world should and might do next from the cavernous ballrooms in the Bellagio hotel.

Hedge fund manager Jamie Dinan, who runs $22 billion York Capital, said he expects interest rates to stay low "longer than people expect."

Both he and Tepper worried more about deflationary pressures than inflationary pressures where the Federal Reserve would be compelled to put on the brakes more quickly.

Like many hedge funds around the world, York has been investing in Europe saying that his fund has been lending to companies by "stepping in where banks aren't going."