Last year, Carlyle Group co-founder David Rubenstein told the conference that he "blew it" when given the chance to be one of Facebook's first investors.
His son-in-law, a classmate of Facebook founder Mark Zuckerberg, tried to set up a meeting between the two men.
Rubenstein didn't take the meeting.
"I asked myself, what are the chances of this guy becoming the next Bill Gates?" Rubenstein said. "So now I have to work for a living."