A downtown office building is heading to a foreclosure auction for the second time this year after the owner failed to close a deal to regain control of the asset.

Philadelphia-based Post Brothers has owned 2100 M St. NW, a 1960s-era, 300K SF office building, since 2023.

Its lender filed to foreclose on the property for the first time in March. At the May auction, Post Brothers cast the winning bid for its own building — a surprising turn of events that even the firm's president struggled to explain.

The development company put up a $60M bid for the property, beating lender AllianceBernstein, which bid $59.5M, the Washington Business Journal reported at the time.

But Post Brothers never finalized that deal.

AllianceBernstein still holds the mortgage for 2100 M, and D.C. deed records show it is now foreclosing on the property again.

The lender filed a foreclosure notice this week, and the filing says an auction is scheduled for 11 a.m. on Aug. 7 at Alex Cooper Auctioneers. A copy of the notice was also sent to Mayor Muriel Bowser.

The filing says the loan has a balance of $77.9M.

The terms of the first auction required that Post Brothers, as the winner, deposit 5% of the bid price within two days of the auction, equating to $3M, and that it close the deal within 30 days.

Post Brothers declined to comment, and AllianceBernstein didn't respond to a request for comment.

Post Brothers purchased the office building in May 2023 for $66.8M with a loan of the same amount from AB. The developer received approval from D.C. planning officials to convert the property into 400 residential units, a renovation that would add five stories and a habitable penthouse.

If that conversion plan doesn't pan out, there is a possibility that the site could become the city's next trophy office building.

D.C.'s development community has been eyeing 2100 M as one of the most enticing sites for a ground-up office development anchored by one of the large law firms looking for new space, several office brokers told Bisnow in May.

It sits in one of downtown's more vibrant areas, near George Washington University and a variety of popular restaurants and cafés. And as trophy office vacancy falls, there is a growing need for a new development.

Post Brothers entered the D.C. market in 2022, buying a pair of mid-20th-century office properties in Dupont Circle from JBG Smith for a residential conversion. The plan to turn the Universal Buildings at 1825 and 1875 Connecticut Ave. NW into 525 apartment units received one of the city’s first three Housing in Downtown tax abatements in September.

Construction hasn't begun, and deed records don’t show that the developer has received a construction loan.

The vast majority of Post Brothers’ portfolio is in Philadelphia. It is nearing completion on a 630-unit apartment project in the south end of the city, the first phase of a development expected to deliver more than 800 additional units.

The company has developed more than 30 properties since its founding in 2006, according to its website, totaling 8,000 apartment units and 700K SF of office and retail.