For 15 minutes, the cryptocurrency industry was euphoric.

At 4:11 p.m. on Tuesday, the official X account of the Securities and Exchange Commission announced that regulators had approved a new investment product tracking the price of Bitcoin, an apparent victory for the embattled crypto industry. Coinbase, a giant crypto exchange, posted a celebratory banner. Crypto fans hailed it as a historic day for the industry.

Then at 4:26 p.m., Gary Gensler, the chair of the S.E.C., posted that the agency’s account had been compromised, resulting in an “unauthorized tweet.” An S.E.C. spokeswoman confirmed the hack in an emailed statement.

The security breach was the latest twist in the crypto industry’s yearslong pursuit of an investment vehicle known as an exchange traded fund tied to the price of Bitcoin. Since the fall, crypto enthusiasts have counted down the days until a Jan. 10 deadline for the S.E.C. to decide whether to allow a Bitcoin E.T.F. Bitcoin’s price has surged more than 60 percent in recent months, driven by the rising optimism that an approval was imminent.

An announcement was widely expected this week, with major financial firms like BlackRock and Fidelity poised to launch the Bitcoin products. On social media, speculation has raged about the exact timing of an approval, inspiring memes about once-obscure S.E.C. procedures and propelling E.T.F. analysts to online stardom.