ProShares’ Bitcoin Strategy exchange-traded fund (BITO) saw the highest ever first day “natural” volume for an exchange-traded fund (ETF), with the figure reaching a little over $1 billion by the end of the opening day.

It is second overall, tailing just behind the BlackRock U.S. Carbon Transition Readiness ETF, which booked $1.16 billion in volume on its debut in April.

The ProShares Bitcoin futures-based ETF launched on the New York Stock Exchange on Tuesday with an opening price of $40.88. According to data from TradingView, BITO closed the day at $41.94, with a total of 24.313 million shares changing hands, equating to a first-day volume of just over $1 billion.

Commenting on BITO’s opening day performance, Bloomberg senior ETF analyst Eric Balchunas tweeted that ProShares’ ETF was arguably the largest in terms of “natural” or “grassroots interest.”

Balchunas said BlackRock’s U.S. Carbon Transition Readiness ETF (LCTU) April launch volume was “unnatural,” as it was driven by “one pre-planned giant investor.” LCTU’s daily volume also fell off a cliff to between $2 million and $6 million in the days after launch.

There was reportedly $570 million worth of inflows for BITO on the first day, suggesting that ProShares’ ETF could rank itself as an industry heavyweight in terms of year-one net flows for a first-to-market single commodity ETF in 12 months.

According to data from FactSet, the top two single-commodity ETFs leading the pack are sold and silver, with year-one flows of $3 billion and $1.7 billion, respectively. Outside of commodities, the largest year-one flow for an exchange-traded product of $5.351 billion was for the Invesco QQQ Trust.

While the bullish performance marks a significant milestone for ProShares and the crypto sector, Balchunas warned that it could have consequences for the other firms next in line to launch their own Bitcoin (BTC) futures ETFs:

“The other result of today is it makes life that much harder for the next in line ETFs to succeed. Time is of the essence. Every day counts because once an ETF gets known as ‘the one’ and has tons of liquidity, it’s virtually impossible to steal.”

Related: Buy the rumor... buy the news? BTC price passes $63K as US Bitcoin ETF launches

Following ProShares’ ETF launch on Tuesday, United States Securities and Exchange Commission Chair Gary Gensler outlined in an interview why he and the SEC favor ETFs backed by Bitcoin futures as opposed to the spot price of BTC.

“BTC futures have been overseen by the SEC’s sister agency, the Commodities Futures Trading Commission, for the past four years. You have something that’s been overseen for the past four years by a federal regulator, and it’s also been wrapped up in the SEC’s jurisdiction through the Investment Company Act of 1940,” he said.

Valkyrie’s Bitcoin futures-based ETF is set to be the second product to join BITO on the NYSE this week. It cheekily changed its ticker to BTFD, which is slang for “Buy The F---ing Dip.”