Ailing Taiwanese phone maker HTC saw its shares slide 6% on the Taipei exchange Tuesday after Winston Yung was replaced as CFO by Chia-Lin Chang, Reuters reported.

Chang is a former Goldman Sachs (NYSE:GS) partner and previously served as an engineer at Motorola. No reason was given for the CFO change. Former CFO Yung will be reassigned to corporate development.

HTC saw rapid growth in 2010 and early 2011, but suffered more recently as newer smartphones from Apple (NASDAQ:AAPL) and Samsung have eroded its market share.

Last November, HTC dramatically cut its earnings outlook. Investors pummeled the stock, which ended the year down 42%. For the first quarter, HTC profits fell by 70% and missed analysts’ already lowered predictions.

HTC released its One series of smartphones last month, featuring faster graphic processors, to mostly positive reviews, but early sales in Western Europe did not show significant gains for the One line. The company also faces headwinds in the approaching launch of Samsung’s newest Galaxy S smartphone.