National Asset Management Inc. boosted its stake in shares of American Airlines Group Inc. (NASDAQ:AAL – Get Rating) by 36.5% in the 1st quarter, according to the company in its most recent 13F filing with the Securities and Exchange Commission (SEC). The fund owned 24,403 shares of the airline’s stock after purchasing an additional 6,525 shares during the quarter. National Asset Management Inc.’s holdings in American Airlines Group were worth $446,000 at the…