Crypto enthusiasts weren’t the only ones watching Bitcoin’s meteoric ascent last month.

The likelihood of a Bitcoin exchange-traded fund gaining approval from the U.S. regulator has declined thanks to the cryptocurrency’s wild price swings in June, Jeff Dorman, chief investment officer at Arca, wrote in a July 1 research note.

The Securities and Exchange Commission has already shot down several ETF proposals, including one from the Winklevoss twins, citing concerns over market manipulation in cryptocurrency markets. Bitcoin’s price rose nearly 50 per cent last month through June 26, only to slide about 20 per cent. Those gyrations were fueled by unregulated exchanges letting users borrow 100 times more than they put down, Dorman wrote, describing it as “unnatural volatility caused by excessive leverage and outsized risk-taking.”

“It’s almost a slam dunk now that an ETF won’t be approved any time soon, as an 81 per cent 14-day levered rally, most of which occurred after U.S. trading hours, is not exactly the formula for successful SEC approval,” he wrote.