Janus Capital Management just can't catch a break. After a long battle, Janus was thought to have finally wrested control from parent Stilwell Financial ( SV) in September, with the restructuring to be finalized in December. Now, though, a Boston hedge fund that is Stilwell's biggest shareholder has raised its stake in the company and hired an investment bank to evaluate whether Stilwell's plan to cede control to Janus is in the best interest of shareholders. Highfields Capital Management, which now owns a 7% stake in Stilwell, hired Blackstone Group to go over the details of the arrangement. The move was disclosed on Monday in a filing with the Securities and Exchange Commission. Highfields said last week it increased its stake to 7%, up from 5.9%. "Highfields has a history of doing this; it's part of how they see themselves as investors," says Morningstar stock analyst Rachel Barnard. "They see themselves as helping the company run its business. But these moves tends to be on the unfriendly side." Recently, Highfields has challenged management decisions at Adelphia Communications and Reader's Digest ( RDA). Barnard expects Highfields' focus to be on Stilwell's ownership of DST Systems ( DST) as well as the sweet deal Janus gets as a result of the reorganization. In an effort to reduce its huge debt, Stilwell said in October that it would consider selling its 33% interest in DST Systems, a provider of investment management services. It's likely that Highfields would want Stilwell to more aggressively seek to unload DST, both to pay off some debt and focus on its core asset management business.