* Loss/shr 0.15 euros vs fcast profit 0.09 euros/shr
* Reports weakest ever quarterly result
* Smartphones mkt share falls to 35 pct from 41 pct in Q2
* Books $1.35 bln hit on networks unit NSN
* Shares down 11 percent in heavy volume (Releads, adds details, updates shares)
By Tarmo Virki, European technology correspondent
HELSINKI, Oct 15 (Reuters) - Nokia Oyj lost ground on the smartphone market to Apple's iPhone and RIM in the third quarter, the Finnish firm said on Thursday, pushing its shares lower.
The world's top cellphone maker reported its worst ever result as it also booked a major writedown in July-September quarter at its struggling networks unit.
Nokia said its smartphones market share fell to 35 percent in July through September from 41 percent the previous quarter.
"The scale of the smartphone market share loss must give the markets pause for thought over the coming days. Dropping six points in three months is pretty stunning," said MKM Partners analyst Tero Kuittinen.
Nokia's Chief Financial Officer Rick Simonson told Reuters the trend should reverse in the fourth quarter as the group rolls out new high-end models like the N97 mini, updating its hit-model N97, and a Linux-software based N900.
"We are going to see improvements there as we are going to see new, fresh models replace older models," Simonson said.
Nokia's smartphones pack more features than Apple's iPhone or RIM's Blackberry, but lack the design and brand-allure of its North American rivals, analysts say.
"Smartphones are about wow-factor. There's different wow for different people. The N900 is probably that for many people," Simonson said.
The company booked a 908 million euros ($1.4 billion) hit from its Nokia Siemens Networks (NSN) joint venture, citing challenging market conditions and dragging the group to a reported loss per share of 0.15 euros.
This was weakest ever quarter for the firm since it started quarterly reporting in mid-1990s.
Analysts expected a 0.09 euros per share profit, according to a Reuters poll of 37 analysts.
Shares in Nokia slumped 10.9 percent to 9.18 euros on the Helsinki bourse, and its U.S. shares were among the top five traded stocks on NYSE, falling 10.7 percent to $13.74 by 1732 GMT.
Shares in smaller vendor Motorola fell 5.2 percent.
Motorola's close rival Sony Ericsson is the next handset vendor to report on Oct. 16.
For a graphic comparing Nokia's share price performance with its peers, click here:
http://graphics.thomsonreuters.com/109/EZ_NKSP1009.gif
SOME LIGHT IN HANDSET BUSINESS
Nokia's key handset unit performed slightly better than expected in the third quarter as consumer demand for mobile devices started to improve in many markets.
"We have actually seen a bit of pickup in consumer demand and looking forward we expect this to continue," said Simonson.
CCS Insight analyst Geoff Blaber said: "Consumer demand may be showing early signs of improvement but these results show sustained pressure on smartphone margins. Apple's iPhone is defying gravity in the high tier."
Apple is expected to report growing iPhone sales when its report September quarter earnings on Oct. 19.
Industry sales of more advanced models, so-called smartphones, rose 15 percent from the previous quarter, Nokia said, but falling smartphone prices are hurting top vendors.
"Nokia is launching plenty of new high-end smartphone models such as the N900 and N97 mini. But as yet there is no iPhone killer to drive a major revival in its smartphone volumes," said Neil Mawston at Strategy Analytics.
HTC, the world's No. 4 smartphone brand, reported worse than expected results last week, underscoring intensifying competition and declining prices.
RIM, the second-largest smartphone maker after Nokia, said on Sept. 24 its profit dropped 3.5 percent in the August quarter and its outlook fell short of forecasts.
Nokia reported a group level net loss of 913 million euros compared with a 1.06 billion profit the previous year. Third-quarter sales fell 20 percent to 9.81 billion.
"Profit margins are under pressure ... Nokia needs to do some serious cost cutting to adjust to weaker demand," said Christian Blaabjerg, chief equity strategist at Saxo Bank. (Additional reporting by Brett Young and Eva Lamppu in Helsinki, Blaise Robinson in Paris; Editing by Elaine Hardcastle and David Holmes) ($1=.6710 Euro)