Warren Buffett remains bullish on index fund investing.
After all, his own company can't beat them.
Buffett has long championed low-cost index funds.
"I think it's the thing that makes the most sense practically all of the time," he recently told CNBC's On The Money.
Index funds are a form of passive investing, and they hold every stock in an index. The S&P 500, for example, owns big-name companies, including Apple, Microsoft and Google.
Buffett told CNBC's Squawk Box recently that if someone invested $10,000 in an index fund back in 1942, it would be worth $51 million today.