India, Oct. 10 -- As fashion franchises like Forever 21 struggle globally amid changing shopping habits and competition from e-commerce, Uniqlo-owner Fast Retailing Co. has managed to turn around a second clothing line into a profit driver.

Its more experimental and stylish GU brand is expected to be a highlight of its full-year earnings to be reported on Thursday afternoon. The sister brand, which sells at lower prices and is aimed at younger customers, had already hit nine-month operating profit of 26 billion yen ($242 million) -- a jump of 75% from a year earlier and accounting for about a 10th of the group's operating profit.

GU's projected growth offers a diversified stream of revenue for the Japanese retail giant at a time when th...