Janus' $150 Billion Problem

In a statement Wednesday, the firm's brief reply was: "Janus Capital Management intends to continue cooperating with the New York Attorney General's inquiry. Janus is reviewing the complaint closely and is committed to ensuring that the company continues to act in the best interest of Janus fund shareholders."

What should Janus fund holders do now? Spitzer told CNBC that investors in Janus -- and, of course, Bank of America's(BAC Quote) Nations Funds, Bank One(ONE Quote) and Strong Capital Management -- shouldn't necessarily "run out and sell their funds" on the news.

Janus also hoped to answer this question for shareholders, in a letter to them that was posted on its Web site. Mark Whiston, Janus' chief executive and president, first noted that the firm isn't mentioned in connection with the more onerous after-market trading allegations -- Spitzer only alleged that Janus and others allowed Canary to market-time. Whiston also noted that Spitzer said it was highly likely that other fund firms would be named.

"Like many other reputable mutual fund families, Janus is concerned about market timing in our industry. To that end, we're reviewing instances where frequent trading may have occurred to ensure that we continue to put the best interests of our fund shareholders first," Whiston said. "I realize that these allegations may be troubling, and I want to assure you that we're committed to the highest ethical standards and to acting in the best interests of you -- our fund shareholders."