The ProShares Bitcoin Strategy exchange-traded fund (ETF) is on track to reach a limit on the number of futures contracts it’s allowed after quickly becoming a little too popular.

After just a couple of days of trading, the ProShares ETF has reached 1,900 contracts sold for October and there is a 2,000 front-month limit imposed by the Chicago Mercantile Exchange.

There are already 1,400 contracts for November and there is an overall maximum limit of 5,000 open contracts according to Bloomberg. One solution could be to offer longer contracts, but that would carry the danger of too much distancing from Bitcoin (BTC) prices.

President of the advisory firm the ETF Store Nate Geraci commented that the fund could start to diverge from market prices, adding:

“The ETF is forced to obtain Bitcoin price exposure at higher and higher prices as it goes further out on the futures curve.”

The launch of competing products such as the Valkyrie Bitcoin Strategy ETF, which will commence trading today, and the VanEck ETF, which is expected to trade on Monday, Oct. 25, may dilute the demand for the ProShares fund.

As reported by Cointelegraph, the ProShares ETF became the first-ever fund to hit $1 billion in assets under management in just two days. It beat an 18-year-old record previously held by a gold-based fund that did it in three.

Bloomberg senior ETF analyst, Eric Balchunas, said that the momentum will still be hard to stop at this point.

“The unprecedented early volume in BITO makes it like a snowball rolling downhill, as liquidity and assets begets more liquidity and assets.”

Related: VanEck Bitcoin Strategy ETF will likely launch next week as crypto prices reach ATHs

Balchunas also thinks that the success of Bitcoin futures products may speed up the approval of a spot-based Bitcoin ETF.

“Both the success, general functioning of ETFs and the clear issue of potential capacity of futures may get the SEC to reconsider or work out a path for spot.”

As reported by Cointelegraph on Wednesday, Grayscale has already anticipated this and is preparing to convert its popular Bitcoin Trust into a physically-backed product based on spot markets.