In recent letters to investors and posts on social media platform Twitter, Gross has recommended that investors buy shorter-dated Treasuries on expectations that the Fed will keep short-term interest rates low until 2016 or later.
The Pimco Total Return Exchange-Traded Fund, an actively managed ETF designed to mimic the strategy of the flagship mutual fund, fell 0.85 percent in December, making it the worst performer of its category for the month and resulting in a drop of 1.2 percent for the year.
That annual return still beat 80 percent of peers, however, according to the preliminary data from Morningstar. Investors pulled $115.8 million from the ETF in December, marking its eighth straight month of withdrawals, Morningstar data showed. The ETF has about $3.5 billion in assets.
Jeffrey Gundlach's DoubleLine Total Return Bond Fund, a competitor to the Pimco fund, fell 0.7 percent in December, beating 19 percent of peers. The fund had outflows of $2.08 billion in December, Reuters reported on Wednesday.
Gundlach's fund, which has about $31 billion in assets and is the flagship of Los Angeles-based DoubleLine Capital LP, rose 0.02 percent last year, beating 88 percent of peers, according to the preliminary Morningstar data.