NEW YORK -- Brokerage firm J.P. Morgan upgraded its stock rating for Brazilian airline Gol Linhas Aereas on Monday to neutral as a price war with its domestic rivals appeared to be ending. "This past weekend, GOL appears to have significantly modified its fare structure," the firm said in a note to clients. "Most importantly, close-in walk-up fares were broadly increased, potentially signaling an end to the multi-month pricing battle that had eroded [unit revenue] performance." In the same note, J.P. Morgan downgraded Tam Sa to underweight because the carrier is less exposed to the improved pricing and its stock price has climbed too high. Shares of Tam were up nearly 4% at last check to $16.69, while shares of Gol rose about 4% to $12.25.

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