Car rental giant Avis Budget has admitted it remains “uncertain” if its proposed acquisition of Dollar Thrifty will meet regulatory approval.

Dollar Thrifty terminated a merger agreement with Hertz in 2010, leaving Avis clear to complete the deal.

However, while Avis said it believed “substantial progress” has been made in discussions with the Federal Trade Commission (FTC), the outcome of the process remains unclear.

Key to Avis’ argument is a belief the deal will not reduce competition in the American rental car industry.

Both Avis and Dollar Thrifty argues intense competition from Enterprise/Alamo/National and Hertz/Advantage, as well as numerous smaller brands, would continue to create sufficient competition after the proposed transaction.

In addition, Avis Budget has expressed the view a merger with Dollar Thrifty would result in significant cost savings and other operational efficiencies.

These synergies and the increased ability of the combined company to compete against other competitors in the marketplace will benefit all rental car consumers, particularly Dollar Thrifty’s core leisure customers.

Both companies have produced millions of pages of documents to the FTC and expect a decision by the end of March or early April.

Dollar Thrifty is being advised by J.P. Morgan and Goldman, Sachs & Co. and the law firm of Cleary Gottlieb Steen & Hamilton LLP.

Citigroup and Morgan Stanley & Co. Incorporated are acting as financial advisors to Avis Budget Group, and Kirkland & Ellis LLP and Arnold & Porter LLP are acting as legal counsel.