BlackRock CEO Larry Fink said an ether ETF would still be possible even if the U.S. Securities and Exchange Commission designates the cryptocurrency as a security, which would increase the regulatory scrutiny around the second-largest digital asset.

Asked Wednesday on Fox Business whether BlackRock – which has made waves in crypto through its bitcoin exchange-traded fund introduced earlier this year – could still list an ETF that holds Ethereum's ether if the crypto is a security, he replied, "I think so."

The SEC is reportedly taking a look at the question of whether ether is a security. Fortune reported earlier this month that the regulator is seeking to classify ether as one and has sent subpoenas to several companies as part of that inquiry.

This caused concern over whether this would mean an ether ETF would even be possible in the U.S.

Read more: Ether Tumbles 6% as ETH ETF Hopes Dim Amid Regulatory Probe Reports

But Fink's confidence is a striking note of optimism.

Eight potential issuers, including BlackRock, have submitted filings with the SEC to bring a spot ether exchange-traded fund (ETF) to the market. The final decision by the regulator is due in May, with industry experts predicting that applications won't get approved, regardless of what the SEC finds the nature of ether to be.

BlackRock is also one of the now-11 issuers of spot bitcoin ETFs. The asset management giant's fund, the iShares Bitcoin Fund (IBIT), is by far the most successful spot bitcoin fund after collecting more than $15 billion in assets after only 2 1/2 months. IBIT is the "fastest growing ETF in the history of ETFs," Fink said on Fox Business.

"Look, I'm very bullish on the long-term viability of bitcoin," he said. "We're creating now a market that has more liquidity, more transparency, and I'm pleasantly surprised, and I would never have predicted that before."

When asked if an ether fund was next, Fink said "we'll see."