Dollar Thrifty Automotive Group Inc (DTG.N), the object of a takeover battle between rivals Hertz Global Holdings Inc (HTZ.N) and Avis Budget Group Inc (CAR.O), said Sunday it wants best and final offers from its suitors by early October.

Dollar Thrifty said both car rental companies have made substantial progress with regulatory reviews, and that the time has come for best and final definitive proposals.

Continuing uncertainty is in no one`s best interest, said Dollar Thrifty CEO Scott Thompson.

Based on the results of this process, we will consider what actions would be in the best interests of Dollar Thrifty and its shareholders, Thompson said in a letter to the CEOs of both Avis and Hertz.

Avis and Hertz were not immediately available to comment.

Thompson cautioned that any proposal that required Dollar Thrify shareholders to assume any portion of the risk of antitrust review would unlikely be acceptable.

Consolidation in the U.S. car rental market has left just four major rivals -- Hertz, Avis, Dollar Thrifty and the industry leader, privately held Enterprise. As a result, antitrust concerns have emerged as a key factor in the battle for Dollar Thrifty.

Earlier this month, the Federal Trade Commission asked Hertz for additional information regarding its proposed takeover of Dollar Thrifty.

Avis is still seeking antitrust approval for its offer.

Dollar Thrifty recently posted second-quarter results below analysts' expectations, hurt by lower per-day revenue, and forecast 2011 revenue to be flat if per-day rental rates remained under pressure in the second half.

The company said Sunday it was positioned for continued strong performance in 2012.

We are optimistic about our future but it`s clear that bringing closure one way or another to the process with Hertz and Avis is in the best interests of our shareholders, the company and our employees, Dollar Thrifty said in a statement.

The battle for Dollar Thrifty has dragged on for 16 months. In May, Hertz offered close to $2.1 billion for Dollar Thrifty, taking advantage of Avis' problems getting regulatory clearance for a rival bid.

Hertz's sweetened offer was more than 30 percent higher than its previous bid and far above the $1.7 billion bid from Avis Budget Group Inc (CAR.O).

After Avis acquired its European namesake in June for about $1 billion, Wall Street's expectations of a higher bid from Avis have significantly come down.