PIMCO Total Return ETF (NYSEArca: BOND) has nearly doubled the performance of the mutual fund version during its first six months as it rapidly approaches $3 billion in assets under management.

From March 1 through Aug. 27, the ETF returned nearly 8.4% compared with 4.5% for the Total Return Fund, the Associated Press reports.

PIMCO Total Return, which is managed by Bill Gross, is the most successful active ETF launch ever.

BOND has been outperforming Total Return Fund, and the smaller ETF class likely gives Gross the ability to be more nimble with trades. [PIMCO ETF Falls In Line with Total Return Fund]

BOND has total net assets of $2.6 billion, while PIMCO Total Return Fund holds $270 billion. In terms of performance, the ETF and the mutual fund are both beating a broad index of U.S. bonds the past six months, according to the AP report by Mark Jewell.

“This is kind of a rock-star ETF, so it’s reasonable to expect the flows will continue to be strong,” said Eric Jacobson, Morningstar’s bond fund research director, in the article. “I would caution against taking the first six months of performance as an indication that the ETF is going to perform better than the mutual fund. More than likely, performance differences between the two will even out.”

PIMCO Total Return ETF

Story updated for correct attribution of Associated Press article.