* Q3 net loss $142 mln vs $478 mln year ago
* CEO blames Q3 woes on higher sales of low-margin chips
PARIS, Oct 23 (Reuters) - STMicroelectronics shares fell as much as 7.2 percent on Wednesday after the European chipmaker reported weak third-quarter results dragged down by mobile chips and pushed back a key profit margin target by six months.
Chief Executive Carlo Bozotti blamed the third-quarter woes on higher sales of low-margin chips for mobiles, compared with lower demand for chips in smartphones like Apple's iPhone .
"Overall the volume was there, but we sold more products in lower-end phones, and less than expected of our chips for higher-end phones," the CEO said.
"I think this is a short-term demand correction, and we are not the only player that has experienced this as we've seen in recent days," he said, referring to results publications and underwhelming fourth-quarter guidance from competitors on Monday and Tuesday.
A host of U.S. chipmakers gave quarterly revenue forecasts that disappointed Wall Street on Tuesday, including Broadcom Corp and programmable chipmaker Altera Corp.
On Monday, Texas Instruments' unexpectedly low fourth-quarter revenue called into question the strength of a recent recovery in chips for automobiles and industrial machines.
Bernstein analyst Pierre Ferragu said STMicroelectronics, unlike some of its rivals, faced difficulties in its mobile-phone-chip product line because of its reliance on customers who are themselves struggling, including Finland's Nokia, Canada's Blackberry and Taiwan's HTC .
"We believe STMicro suffered from its continued exposure to losing smartphone manufacturers," Ferragu wrote in a note.
He estimates that Nokia, Blackberry and HTC account for 10 percent of STMicroelectronics' sales.
The group also lost a key contract for chips in Apple's new iPhone 5S to Bosch, but the impact from that is not likely to appear until the next few quarters, JPMorgan analysts said.
Bozotti declined to talk about specific customers, but argued that STMicroelectronics now had a wider array of products for high-end smartphones, which should eventually pay off in the form of better margins.
"After the ST-Ericsson exit, our exposure to Blackberry is pretty limited," he added, referring to the shutdown completed in the third quarter of a loss-making mobile chip joint venture.
Franklin Pichard, a director at Barclays Bourse, an advisory firm for investors, called the third-quarter results "disappointing" but said the share price drop was too "severe".
STMicroelectronics had a third-quarter net loss of $142 million, compared with a net loss of $478 million a year ago.
"We recommended the shares when they were trading around 7 euros," Pichard said.
STMicroelectronics shares were trading at 5.951 euros at 0935 GMT. Before the results publication, the stock price had risen 21 percent this year to close at 6.37 euros on Tuesday, in line with the European technology index. (Reporting by Leila Abboud and Alexandre Boksenbaum-Granier; Editing by James Regan)