After winning bet against hedge funds, Warren Buffett says he'd wager again on index funds

Warren Buffett, chairman of Berkshire Hathaway Inc.
Lacy O'Toole | CNBC

The chairman and CEO of Warren Buffett said Tuesday that passive investing works in any market environment and so he'd be willing to wager again against active investing for the next 10 years.

A decade ago, the billionaire investor made a million dollar bet that the S&P 500 will beat a basket of fund of hedge funds over the next 10 years, ending this year. He will likely win that bet by a large margin.

The S&P 500 "will absolutely kill every one of the fund of funds," Buffett said on CNBC's "Squawk Box." "Passive investment in aggregate is going to beat active investment because of fees."

The investor explained if you don't pay 2 percent or 3 percent of fees to financial advisers, the your payoff for investing in the broad market will be "very good" over time.

When asked if he just got lucky with the timing of the bet, the Buffett said "the date of the start has nothing to do with it."

He said is willing to do another bet on active versus passive as long as anybody wants to put up "a significant percentage of their net worth" on the wager.

Buffett joined CNBC from Omaha, Nebraska — home of Berkshire and where Purpose Built Communities was holding its annual conference.