Noted investor Mark Mobius said Wednesday that he expects a 30 percent drop in U.S. stock markets as a result of massive outflows from exchange-traded funds.

"I think a 30 percent correction in the [U.S.] markets is not unforeseen," Mobius, co-founder of Mobius Capital Partners, said on CNBC's "Power Lunch."

"I think this is quite possible. I'm not predicting it tomorrow or next week, but what I'm saying is that the way the structure of the market has now developed with ETFs, when they decide to sell or their computers decide to sell, you're going to see big corrections," he said. "So we have to be ready for the volatility."