JBG relied on principals Paul Hanafin and Richard Siegel of West, Lane & Schlager's Investment Services Group, while Perseus was represented internally. The building and the quarter-acre it occupies in the District's Foggy Bottom neighborhood have a combined current assessed value of $22.9 million.

"This is one of only a handful of dedicated medical office buildings in the District," Hanafin notes. "Since the mid-80's, we've built tens of millions of square feet of office buildings, and haven't added a foot of new medical space." Additionally, the building is in an area that is currently the site of a great deal of multifamily development. JBG added the Atlas Condominium as a separate property abutting the medical office building. The condo project has an address on 25th St. and was not part of the transaction. "They recognized the value of the site long ago, extracted significant development potential and timed the market perfectly for delivering residential condos and selling the office building," Siegel adds. Perseus plans further upgrade 2440 M St.