Greenlight Capital's David Einhorn, who is known for his prescient short bets against stocks like Lehman Brothers, shared the top reasons for his stellar hedge fund career.

The billionaire hedge fund manager was asked what he believed is the most important factor for his investing success during an Oxford Union event last month.

"If I had to pick one, I think it is critical thinking skill. It's the ability to look at a situation and see it for what it is, which isn't necessarily what is presented to you," Einhorn said. "And when something makes sense to figure out what makes sense. And when something doesn't make sense to question it, to challenge it, to look at it from a different way, to often come to the opposite conclusion."

The full 50-minute interview was posted Dec. 15 on Oxford Union's YouTube channel. Oxford Union is the speaking and debating society at the University of Oxford. The event was held Nov. 15.

The investor also explained why his fund bets big when these high conviction opportunities come:

"You don't have to do it very often. Most of the time when someone tells you something and it makes sense, it just makes sense. And that's that. But sometimes it really doesn't make sense … And when you can come to a view maybe just a few times a year, where you have an important difference of opinion with what everybody else is thinking about a particular situation, if you can figure that out and figure it out it is important, we've been able to make a small number of large investments that the vast majority of the time … worked out very well."

Einhorn's hedge fund, Greenlight Capital, was up 6.2 percent in the third quarter, bringing its performance for 2017 through September to 3.3 percent compared with the S&P 500's 14.2 percent return, according to an investor letter to clients. From inception in May 1996 to the end of 2016 the fund generated annual returns of 16 percent.

The YouTube video of the interview had 12,000 views as of Tuesday morning.