The U.S. Securities and Exchange Commission is investigating whether former junk-bond pioneer Michael Milken acted as an adviser to Guggenheim Partners LLC in violation of a lifetime ban from the securities industry, a person with knowledge of the matter said.

Investigators are reviewing whether Milken, an investor in the $170 billion asset-management firm, has in effect managed other clients’ money by playing an active advisory role to the firm, said the person, who asked not to be named because the matter isn’t public. Neither Milken nor Guggenheim has been accused of wrongdoing.

Milken, the former head of junk-bond trading at Drexel Burnham Lambert Inc. in the 1980s, served 22 months in prison and after pleading guilty to securities fraud in 1990 and was permanently barred from serving as a broker or investment adviser. In 1998, Milken agreed to pay $47 million to settle SEC claims he had violated the ban; he didn’t admit or deny wrongdoing.

Guggenheim gained attention last year after it joined a group that bought the Los Angeles Dodgers for $2.15 billion. The firm in September agreed to buy Dick Clark Productions, which produces “New Year’s Rockin’ Eve” and “The Golden Globes,” along with Mandalay Entertainment and Mosaic Media Investment Partners LLC.

According to Fortune magazine, which reported the investigation earlier today, the firm has handed over documents including trading records and emails in response to an SEC subpoena. Investigators are reviewing transactions that Milken has done jointly with Guggenheim, Fortune said.

Torie von Alt, director of public relations at Guggenheim, declined to comment. SEC spokesman John Nester also declined to comment.

Post-Prison Philanthropy

In the two decades since his release from prison, Milken has become known for high-profile philanthropy, funding prostate cancer and epilepsy research and providing college scholarships through the Milken Family Foundation.

In response to a request for comment, Geoffrey Moore, a senior advisor to Milken, provided a link to a statement given to Fortune. In that statement, Milken said he discusses his and his family’s investments with advisors and money managers from time to time, but only as an investor. He has had no desire to be in the securities business in any capacity and has strictly avoided doing anything that could be interpreted otherwise, according to the statement.