The company's new deadline for the offer for up to 14.2 million shares at $84 each is 11:59 p.m. EDT on Oct. 5.
All other terms and conditions of the tender offer, part of a multi-tiered deal Dubai World has cut with the gambling giant, remain unchanged.
As of the close of business on Sept. 24, MGM Mirage stockholders had tendered just 730,271 shares.