The person who oversees BlackRock Inc.’s iShares exchange-traded funds says he can’t see the asset manager launching a bitcoin or virtual-currency ETF.

“We said our whole product line is being products that we would encourage our clients, whether they’re individuals or institutional, to hold in perpetuity,” BlackRock’s Mark Wiedman told Bloomberg TV’s Erik Schatzker in an interview. “

I would not encourage a client to hold bitcoin in perpetuity.”

Wiedman said ETFs are meant to capture trading products that are otherwise difficult to access, and bitcoin doesn’t fit that bill.

“If bitcoin is ever successful -- again not my thing and I wouldn’t recommend it -- but if it were, why would you need an ETF to access it?” he said.

Other firms are seeking regulatory approval to create ETFs linked to bitcoin, but the U.S. Securities and Exchange Commission has yet to sign off on any. ProShare Capital Management is trying to launch a pair of ETFs tied to bitcoin futures contracts, and other firms have already filed with the agency to create about half a dozen ETFs linked to the digital currency, whose price has soared almost sevenfold in the past year.

Wiedman also dismissed the idea of “orphaned stocks,” the concept that ETFs create distortions in the market as certain securities picked up in popular funds rise in value while others get left behind. BlackRock offers 400 ETFs in the U.S., he said, so it’s unlikely a stock hasn’t been included in an index.

“It’s about thinking about how people actually use ETFs today as opposed to worrying about the orphaned stock,” he said, adding: “by the way, if there is an orphaned stock out there, I suggest you buy it.”