(Reuters) - Group 1 Automotive (GPI.N), the United States' fourth-largest U.S. auto dealer group, has agreed to buy Brazilian automotive retail firm UAB Motors Participacoes S.A for about $146 million in cash and stock, to expand into Brazil's fast growing market.

Group 1 said on Thursday it reached a definitive agreement to buy UAB for $47.4 million in cash and 1.45 million Group 1 shares, valuing the deal at about $145.6 million based on Group 1's close on the New York Stock Exchange on Thursday.

The U.S. auto dealer, which will also assume about $62 million of UAB debt, said the deal should be modestly accretive, adding 3 cents to 5 cents a share to its 2013 earnings.

The deal will give Group 1 ownership of 18 dealerships -- two Toyota, four Nissan, two BMW, two BMW/MINI, three Renault, three Peugeot, one Land Rover and one Land Rover/Jaguar -- which are expected to generate about $650 million in annual revenues.

"To enter one of the largest auto markets in the world with a well-established retail infrastructure and management team provides Group 1 and our shareholders with an incredible growth opportunity," Group 1 chief executive Earl Hesterberg said in a statement.

The deal is expected to close around February 28, 2013.

(Reporting by Zeba Siddiqui in Bangalore; Editing by Richard Pullin)

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