Taiwan's HTC Corp said it expects revenue to fall as much as 30 percent in the third quarter compared to the previous quarter, far below analysts' forecasts, citing fierce competition in the mid-range to high-end smartphone markets.

The firm indicated a weak outlook for profit margins.

"Our overall gross margin has been impacted by a relatively higher cost structure, lack of economy of scale and certain provisions needed to facilitate the clearance of aging products," it said in a statement.

HTC said it expects revenue this quarter of between NT$50 billion ($1.7 billion) and NT$60 billion,  and it reported revenue of NT$70.7 billion in the previous quarter and NT$70.2 billion a year ago.