Whitney Tilson - "Shorting saved my butt in 2008. … Shorting kept me in the game."

Tilson was up nearly 17 percent and 14 percent in 2013 and 2014 respectively, only to lose ground again last year, by about 7 percent. His fund is currently about $70 million in size.

By 2013, he had separated from his investment partner, relaunched Kase Capital, which he started in 1999, as a solo venture and set his sights on making up his lost ground.

The public is most familiar on the program about the mortgage crisis in 2008.

He opened up about this experience:

"It's not about the money," he said "It's more about pride and wanting to do well for my investors."

"My returns my first 12 years were much better than my returns the last five years," he said, but his experience has deepened.

"I'm a massively better investor today than I was my first five and my first 10 years. And yet my returns don't reflect that. And so that's a question I'm always grappling with," he said.

"Because I'm a very public figure, everybody knows what my returns are," he said.

I can survive. I'm 49 years old," he said, "and I plan to be doing this another 50 years. So I'm 18 years into a 68-year-run, is the way I view it. I'm playing the long game."

Indeed, his single-biggest position is in Warren Buffett's stolid Berkshire Hathaway, a company and a man he has written much about and studied closely. The short positions, like Lumber Liquidators or Herbalife, are a much smaller part of his portfolio, although they often attract the most attention.

These short positions are critical to his strategy, though. "It's sort of disaster insurance," said Tilson. "Shorting saved my butt in 2008. … Shorting kept me in the game. It generates cash when the market's crashing. And that's what you want when the market's crashing — cash."

That's not to say he'd recommend it to just anyone.

"My advice to most people is don't short stocks," he said. "It's a very, very difficult business. And you can really get clobbered," like he has shorting Tesla.

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