"It's a phenomenal location," one investment sales professional says of the well-known building, which was first put on the market in late 2006 after school officials decided a combination of the hot real estate sales market and their desire to be in a more streamlined educational facility made a disposition strategy prudent. That initiative has been slowed, however, partly by the school's inability to identify a suitable replacement site. But while the process has been extended, sources maintain Congress Group has managed to put an agreement together. "It's them," one source claims of the firm founded by Dean Stratouly. That firm has already made its imprint on the local skyline through the Museum Towers apartments in Cambridge and 33 Arch St., Boston's newest office tower, where Congress Group is headquartered.

At this point, parties involved in the discussions have yet to respond to the multiple rumors of a deal with Congress Group. Calls to Stratouly and Charter School officials were not returned by press deadline. Brokers at CB Richard Ellis, whose capital markets group has a diverse team of professionals working to sell 100 Arlington St., also did not respond. The brokers include principals Chris Angelone, Patrick Cavanagh and William Moylan along with hotel expert David McElroy.

Whatever plans Stratouly might have for the building remain unanswered, but he did publicly announce, when the asset first became available in 2006, that he considered 100 Arlington St., a prime spot for a hotel. The asset was also advertised for potential conversion to office or retail space. Given Stratouly's vocal admiration for the structure, observers say they are not particularly surprised to hear that Congress Group has the asset under agreement, although the process had been so drawn out that some expressed surprise it was still on the market.