The future of Boston’s largest bookstore, Barnes & Noble at the Prudential Center, is uncertain.

According to a commercial real estate broker with knowledge of the situation who asked for anonymity, the bookstore’s lease is about to expire and the chain has not entered negotiations to renew with Boston Properties, the Prudential Center’s owner.

Barnes & Noble is the country’s largest book chain and its Boston store has consistently been one of the company’s most profitable locations. The chain was publicly held until acquired in 2019 by private equity firm Elliot Management. During the pandemic, Barnes & Noble temporarily closed 400 of its 620 stores.

The Boston store occupies 36,000 square feet and is the Prudential Center’s largest retail tenant. It combines book sales, coffee shop and is noted for lectures and book signings. Spokespeople for Barnes & Noble and Boston Properties did not respond to requests for comment.

A knowledgeable source who also requested anonymity said that the Harvard Book Store which is owned by Boston Globe and Red Sox owner John Henry has expressed interest in acquiring at least some of the space.