The departure took Express employees as well as students by surprise. Express Spokesperson Tara Savin said the store was not in financial trouble.

The decision to leave, rather, came after representatives of C.B. Richard Ellis company, the property's landlord, approached Express, saying the company had received a better offer for the space, Savin said.

"Our decision to move was a real estate decision," Savin explained. "The landlord of the property had another, better offer and we decided to relinquish the space."

Once the landlord approached Express, the decision was fairly simple, Savin said.

"While we didn't initiate the decision to move, it just made sense for everybody," she said. "It will give the new tenant and the landlord an opportunity to make some money."

Though Express and Structure were not in financial trouble per se, the decision to vacate was nonetheless motivated by financial concerns.

The fact that a national chain, which was blessed with immense popularity among Harvard students and perpetual long lines at its registers, still chose to leave is a testament to the Square's steepening rents.

"There are questions about why a space like that couldn't survive," said Robin Lapidus, director of the Harvard Square Business Association.