Eric Noll, head of transaction services at Nasdaq OMX, during the hearing said ETFs shouldn’t be blamed for market volatility, but rather uncertainty over the European debt crisis, government finances, troubled banks, unemployment and other challenges. [Senate Hearing on ETFs]

“The returns from ETFs are far better than mutual funds or other forms of investment management, period,” said Steinhardt, who closed his hedge fund in 1995 after a brilliant run. “No close comparison. And that’s the reason why ETFs are popular.”

He said if some leveraged and concentrated ETFs, for example, “reach a point where they dominate limited markets,” then regulators should do something about it. “It’s a minor issue in ETFs. And if it really exists, there are mechanisms by which that can be controlled. I don’t see it as a major problem,” Steinhardt told CNBC.

WisdomTree manages nearly $12 billion in ETF assets. The firm is planning a share offering. [WisdomTree Readies Share Offering Before Q3 Results]