BOSTON (AP) — It now has six months under its belt. Back in March, star bond trader Bill Gross launched an exchange-traded fund version of the PIMCO Total Return bond mutual fund. It was the most eagerly awaited ETF launch ever, due to Gross' credentials and the strong record of the world's largest mutual fund.

That's not a long time, but the PIMCO Total Return ETF is hard to ignore, thanks to its surging out-of-the-gate performance and initial success at attracting cash.

From March 1 through Aug. 27, the ETF returned nearly 8.4 percent — impressive for a fund focusing on bonds, which tend to appreciate in value more slowly than stocks, with less volatility. Performance has been even more eye-catching measured against the Total Return mutual fund, which pursues essentially the same strategy as the ETF. The fund has returned 4.5 percent, nearly four percentage points behind the ETF. Both are outperforming the 2.6 percent return for a broad index of U.S. bonds.