Las Vegas-based Wynn received its Massachusetts license in 2013, allowing it to go ahead with building the 671-room Encore Boston Harbor in Everett, Massachusetts. It is expected to open in June.
The talks over a possible sale has been on for the past several weeks and were in the "very" preliminary stages, but that would not delay the opening of the casino, the companies said in an emailed statement to Reuters.
A deal would be complicated for MGM, which has a casino in Springfield, as according to the state's gaming commission Massachusetts forbids companies from holding more than one casino license in the state.
The Massachusetts Gaming Commission had in April fined Wynn Resorts $35 million for not disclosing sexual misconduct allegations against founder and former chief executive officer Steve Wynn, but allowed the casino operator to keep its license.