ProShares on Thursday introduced the "Ultra CRCL" exchange-traded fund, the first U.S. single-stock product designed to provide twice the daily return of Circle Internet Group shares (ticker CRCL). The fund began trading on Aug. 7. The issuer submitted its prospectus only 60 days ago, beating the Securities and Exchange Commission’s typical 75-day review period for new ETFs. The accelerated approval highlights continued demand for highly leveraged vehicles that let retail investors amplify short-term moves in individual equities. The launch follows a rough stretch for Circle, whose stock has fallen about 25% over the past month, a slide that could magnify volatility for investors in the new 2x product.