Bitcoin hovered on Thursday below its all-time high struck a day earlier after the launch of the first U.S. bitcoin futures exchange-traded fund, though J.P. Morgan analysts voiced doubt over its impact on cryptocurrency investment flows.

The world’s largest cryptocurrency traded flat at $66,032, erasing slim losses made in Asian trading hours, after hitting a record $67,016 on Wednesday.

Bitcoin’s rally to its latest peak – six-month after its previous top of $64,895 – was fuelled by the launch of the ProShares Bitcoin Strategy ETF. Investors have bet this will open a path to greater investment from both retail and institutional investors.

Yet some analysts at major banks voiced doubt over how long-lasting the boost to bitcoin prices from the ProShares ETF, which trades under the ticker BITO, would be.

“Will the launch of BITO by itself bring significantly more fresh capital into bitcoin? We doubt it given the multitude of investment choices bitcoin investors already have,” J.P. Morgan analysts wrote in a note.

“The bulls are seeing this ETF as a new investment vehicle that would open the avenue for fresh capital to enter bitcoin markets. The bears are seeing the new ETF as only incremental addition to an already crowded space of bitcoin investment vehicles.”

Many market players see inflation risks, rather than new investment products, as driving bitcoin’s recent rally. The cryptocurrency’s limited supply makes it, proponents say, a useful vehicle for hedging against rising inflation.

Still, others predicted that bitcoin’s latest peak would open the way to further gains this year.

“We think it’s going to go higher and we can get to $80 or $90,000 by the end of this year easy, but that won’t be without volatility,” said Matt Dibb, COO of Singapore-based Stack Funds.

In the past few days, he said, traders were starting to pay high rates to borrow to buy bitcoin futures, “and that’s a sign that we could be a bit overextended, and there could be a pullback to come.”

Ether, the world’s second largest cryptocurrency, rose 1% to $4,203 – close to its all-time high of $4,380, hit in May.