NEW YORK (CNN/Money) - Janus Capital Group Inc. said Thursday that one of its clients intends to pull out approximately $5 billion, or nearly 3.7 percent of its total assets under management, from its mutual funds by the end of the year.

The Denver-based mutual fund company said total assets under management stood at $135.4 billion at the end of June. A Janus spokesperson told CNNfn that the client's decision was "somewhat of a surprise." Janus would not identify the client.

The client's board of directors needs to approve the decision.

"We're disappointed when any client comes to this conclusion, especially given our improved performance and the steps we've taken to put our fund holders first," Steve Scheid, CEO of Janus, said in a statement.

Thursday's announcement comes after Janus (JNS: Research, Estimates) reached a $226 million settlement in April with state and federal regulators over accusations it allowed abusive trading in its mutual funds to the detriment of investors. Investors in Janus funds have redeemed about $28.5 billion over the past nine months.

A banking analyst who spoke to CNNfn today indicated that the magnitude of this redemption is "considerably larger than anyone would have anticipated." The analyst went on to say that today's news would not necessarily lead to an exodus of client funds but that it certainly would not help Janus' weak sales.