ProShares Short Ether Strategy is designed to deliver the inverse of the daily performance of the Standard & Poor's CME Ether Futures Index. In other words, if the index falls 1%, the ETF will seek to return 1%.

Like other cryptocurrency ETFs, the new product is tied to futures contracts on ether, rather than the spot price for the token. The market is still waiting for the U.S. Securities and Exchange Commission to give the green light to spot bitcoin ETFs.

The first ether ETFs made their debut as a group in early October, with Proshares launching three of the nine new vehicles. The ProShares Ether Strategy ETF offers exposure to ether only; the other two combine exposure to ether and bitcoin.

That debut was underwhelming, especially when compared to the success of the ProShares Bitcoin Strategy ETF, which pulled in about $1 billion in assets within its first few days of trading. By contrast, the largest of the new ether futures ETFs has below $10 million in assets.

Michael Sapir, CEO of ProShares, said in a statement that the new inverse ether ETF is designed "to address the challenge of acquiring short exposure to ether, which can be onerous and expensive."

ProShares also offers an inverse bitcoin ETF, ProShares Short Bitcoin Strategy. That fund has about $74 million in assets.

Roxana Islam, head of sector and industry research at VettaFi, noted that while the market is eagerly anticipating final SEC approval for spot-based cryptocurrency ETFs, it makes sense for ProShares to launch an inverse ether product.

"This kind of inverse strategy can't easily be displaced or replaced by a spot product," she says.

(Reporting by Suzanne McGee; Editing by Ira Iosebashvili and Deepa Babington)

By Suzanne McGee