(Telecompaper) The chief operating officer (COO) of Taiwanese smartphone maker, Matthew Costello, has stepped down following a slump in profits and delayed product launches, Bloomberg News reports. His responsibilities have been taken over by Fred Liu, president of engineering and operations. In an e-mail to employees, seen by Bloomberg, Liu said that his expanded role covered operations, quality, sales operations and services. HTC confirmed the news to Bloomberg, adding that Costello would stay on as an executive adviser. Liu's e-mail also said that HTC would establish a new quality assurance division, led by Georges Boulloy, with a team handling product lifecycle matters.