Aion Partners paid $30.2 million to buy out its partner’s stake in a 135,000-square-foot Midtown East office building.

The investment company now owns 100 percent of 11 East 44th Street after buying Clarion Partners’ [TRDataCustom] stake in the building, Michael Betancourt, founding partner of Aion, told The Real Deal. He declined to discuss further details of the deal, and a representative for Clarion could not immediately be reached for comment.

Aion initially purchased a 77.1 percent stake in the building from Kensico Properties in December 2004 for $45.5 million. Three years later, Clarion bought into the building, though property records don’t indicate the details of that deal.

In August, Deutsche Bank and SL Green Realty provided $80 million to refinance the building and acquire Clarion’s stake. The financing, which replaced an earlier $38.5 million loan, included a $65 million senior mortgage from Deutsche and a $15 million mezzanine loan from SL Green. Property records filed with the city’s Department of Finance on Tuesday show that Aion paid Clarion $30.2 million.

The office building — located at Madison Avenue and 44th Street — spans 135,150 square feet across 42 floors. Brooks Brothers, which occupies 40,395 square feet, is the building’s biggest tenant. Asking rents in the building range from $36 to $65 per square foot, according to CoStar.