UPDATE 1-Asustek cuts shipment target on Europe fears

* Q2 net T$3.32 bln vs consensus forecast T$4.27 bln

* Sees Q3 portable PC shipments flat vs Q2

* Sees Q3 sales up 5-10 pct vs Q2; trims 2010 shipment target

* Stock up 4 pct before results (Recasts with company quotes, analysts' comments and details)

TAIPEI, Aug 13 (Reuters) - Netbook PC pioneer Asustek (2357.TW) posted a weaker than expected second-quarter profit and trimmed its laptop shipment forecast for this year as it sees uncertainties ahead in European and U.S. markets.

Asustek Computer Inc said on Friday it expected combined shipments of its regular notebook and low-cost netbook PCs to reach 4.1 million units in the third quarter, versus 3.9 million in the second quarter.

Asustek CFO David Chang said the company's third-quarter sales would rise 5-10 percent from the second quarter, while 2010 combined laptop shipments would reach 16-17 million units, lower than an earlier estimate of 18 million units.

"Margins were not good in the second quarter and that's mainly because of the currency issue. It looks like demand is not strong into the second half," said Angela Hsiang, a technology analyst at Taiwan's KGI Securities.

"We used to see a sequential rise of 20 percent in its sales in the third quarter, and you can see the growth this year is worse than the past several years."

Technology sales typically peak in the third quarter on to back-to-school demand and pre-Christmas buying before slowing into the fourth quarter.

"We encountered the debt problem in Europe in the second quarter this year and we will still feel the pain in the third quarter," Asustek's Chang told an investor conference.

Europe made up 39 percent of the firm's total sales in the second quarter, versus 41 percent for Asia.

"So far, three major markets are not doing well, so we are conservative about the third quarter," CEO Jerry Shen told the same conference, referring to Europe, China and the United States.

Asustek, which also produces motherboards and sells mobile phones under its own name, made a net profit of T$3.32 billion ($104 million) in April-June, compared with a net loss of T$131 million a year ago when it was hit by foreign exchange losses.

The profit was down by a third from the first quarter of 2010 and fell short of a consensus forecast of T$4.27 billion by Thomson Reuters I/B/E/S.

The results came after the Taipei stock market closed on Friday. Asustek shares rose 4 percent, outpacing the main TAIEX share index's .TWII 0.8 percent gain.

Hit by worries over slower demand, the stock has fallen about 18 percent so far this year, versus the big board's 4 percent fall in the same period.

Earlier this week, Acer Inc (2353.TW) reported a 38 percent fall in its sales in July, while Acer still expects its brand revenue to grow 10-15 percent in the third quarter from the second quarter. [ID:nTPV001845]

Asustek pioneered the low-cost netbook PC in 2007 but has been rapidly losing market share as bigger rivals such as Acer, global leader Hewlett-Packard Co (HPQ.N) and Dell Inc (DELL.O) entered the netbook sphere.

Pegatron Corp (4938.TW), the manufacturing unit of Asustek, was spun off to avoid any conflict of interest in Asustek's main business of selling laptop PCs and its work making gadgets for other brands. (US$1=T$32) (Reporting by Baker Li, Editing by Jonathan Hopfner)