According to Laibson, Harvard has had an official offer on the table for a little over a year, but has been wooing him for far longer than that.

Laibson said he could not comment on whether or not Harvard had offered any added bonuses to the tenure offer in order to seal the deal with Mullainathan.

“Those details are known only to Sendhil and the powers that be,” Laibson said.

Laibson wrote in an e-mail yesterday that above all he is simply happy to have Mullainathan moving down the river.

“I am absolutely thrilled that Sendhil has chosen to join us,” Laibson wrote.

Benjamin echoed Laibson’s statement.

“I know that the Harvard faculty has been putting a lot of effort into trying to convince him to come here,” Benjamin said. “He is widely considered to be one of the top stars in economics.”

Bengt Holmstrom, the chair of the economics department at MIT, could not be reached for comment.

—Staff writer Evan M. Vittor can be reached at vittor@fas.harvard.edu.