NEW YORK ( TheStreet) -- Investors continued to bid up shares of Brazil's largest airliner Wednesday.American depositary receipts of TAM ( TAM) gained 8.1% to $21.80, their highest point in six months. The stock-price gains occurred as the market digested a series of positive news on the company. TAM recently acquired a small regional Brazilian airline as it strives to widen its footprint at home. And just a week before, TAM said that it planned to sell shares of its Multiplus frequent-flyer unit to the public in an IPO on the Sao Paulo Stock Exchange. Like its smaller rival, GOL Linhas, TAM wants to increase its mileage programs to take advantage of the Brazilian economic recovery. GOL Linhas' ( GOL) New York-listed issues also gained ground Wednesday, adding 4.8% to $15.20. U.S. airline stocks were weaker by comparison Wednesday, weighed down by rising crude oil prices. AMR AMR ( AMR) is down by 0.3% to $8.10 and AirTran ( AAI) has fallen by 1.3% to $5.30. Continental ( CAL) dipped 0.9% to $18.40. -- Reported by Andrea Tse in New York Follow TheStreet.com on Twitter and become a fan on Facebook.