"It is on the market," concurs a source tracking the activity, with Grubb & Ellis, said to be orchestrating the sales process on behalf of Dupont Family Properties of Webster, MA. Calls to G&E were not returned, but industry watchers say the assignment is being handled by brokers Philip Giunta and Karyn McFarland. Efforts to contact Dupont officials by press deadline were unsuccessful.

Despite the silence among those involved, sources insist Dupont is harvesting the buildings after spending the past decade assembling the portfolio. One broker familiar with the buildings describe them as generally "well-maintained," but said there would likely be some needed capital improvements under new ownership. Besides 101 Tremont St., sources say the buildings being sold include 37-39, 45 and 55 Bromfield St.

As to the potential for a redevelopment of the block, the broker says nearby historic attractions could make it difficult to win height allowances on a tight footprint, although the properties are near the 19-story Nine Zero Hotel, erected earlier this decade. The lack of input about the sale makes it difficult to peg a price, but observers say they believe investors will be attracted to the opportunity. Among the perceived strengths is a location in the heart of Boston's most vibrant shopping district, one increasingly seeing new uses, such as offices and condos. The area is expected to receive a major boost when Gale International and Vornado Realty Trust complete a 1.2 million-sf expansion of the nearby Filene's Department Store into a mix of hotel, office, residential and retail space.