New Jersey's Casino Control Commission granted approval Monday with the support of the state's Division of Gaming Enforcement.
The planned sale came about because New Jersey regulators found that MGM's business partner in a casino in the Chinese enclave of Macau is "unsuitable" because of her father's reputed connection to Asian organized crime.
MGM decided it would rather sell its piece of the Borgata than cute ties with Pansy Ho, whose father, Stanly Ho, denies any ties to gangs.
The Borgata's other owner, Boyd Gaming, has passed on buying MGM's half.
The deadline for a deal is now March 24, 2013.