By Kirsten Grind 

Pacific Investment Management Co. said investors pulled $23.5 billion from the Pimco Total Return fund in September, the largest monthly outflow at the firm ever and the latest sign of the fallout from the abrupt departure Friday of the bond world's biggest name, Pimco founder Bill Gross.

Pimco said in a statement Wednesday afternoon that the largest daily outflow took place the day Mr. Gross resigned to take a position at Denver-based Janus Capital Group Inc. A spokesman for Pimco declined to comment.

The company statement said investor outflows were "considerably smaller" Monday and Tuesday, without giving figures.

"We are confident that the vast majority of them will continue to stand with Pimco as we demonstrate why we have earned the reputation as one of the world's premier investment managers," the Newport Beach, Calif.-based firm said in the statement.

The Pimco Total Return fund, which held $222 billion in assets at the end of August, already has seen more than $65 billion leave the fund since May 2013. In August, the fund saw a net $3.94 billion in redemptions.

Min Zeng contributed to this article.

Write to Kirsten Grind at kirsten.grind@wsj.com

Subscribe to WSJ: http://online.wsj.com?mod=djnwires