The Pimco Total Return Fund, the world's largest bond fund run by Bill Gross, is trailing 87 percent of its peers so far this year despite returning to gains after a rough 2013, Morningstar data show today.

The Pimco Total Return, the Newport Beach, Calif. firm's flagship portfolio, is posting returns of 1.28 percent year-to-date as of March 27, trailing the benchmark Barclays U.S. Aggregate index by 75 basis points for the same time period, according to Morningstar.

Pimco, which oversaw $1.91 trillion in assets as of December 31 according to the firm's website, has been in the spotlight since January's announcement that Mohamed El-Erian was resigning as Pimco's chief executive officer and co-chief investment officer.

February was a particularly brutal month for the Pimco Total Return Fund, which only held 9 percent in U.S. credit which may include both high-yield and investment-grade securities.

Eric Jacobson, Morningstar senior analyst, said: "The fund was very underweight U.S. investment grade corporate bonds. That would have been a detriment given that the overall investment grade corporate index returned 104 basis points for February, and returns were better the farther down you went on quality."

The fund also cut its effective duration to 4.71 years in February from 5.05 years. Jacobson said the fund's shortening of duration and meaningful underweight to bonds maturing in more than five years and all the way out the yield curve "would probably have been a very meaningful detriment to returns because the 20-plus sector of the Treasury index returned 85-plus basis points for February."