Bitcoin has rallied for months ahead of the expected launch of the first U.S. exchange-traded funds to hold the cryptocurrency. Skeptics say it is nearly out of room to run.

The Securities and Exchange Commission could approve the funds, known as spot bitcoin ETFs, as soon as next week. Approval would mark a watershed moment for the industry, allowing investors to purchase bitcoin in their brokerage accounts as easily as stocks. (Funds that track bitcoin futures are already on the market.)