Pimco's flagship Total Return Fund saw an estimated $23.5 billion in outflows in September, the investment firm said Wednesday.
This means the fund saw a drain of more than 10 percent of its total net assets in one month, according to data from Morningstar, which assessed it at $221.61 billion as of Aug. 31.
Co-founder and longtime Chief Investment Officer Bill Gross announced last week that he would be leaving.
"Of note, the largest daily outflow occurred on the day of Bill Gross' resignation from the firm, while outflows on the two following days were considerably smaller," the firm said in a press release.
Pimco, which is owned by Allianz, said its Total Return Fund, "is well positioned to meet potential redemptions."