* Expects 2012 sales to rise 40-45 pct vs 60 pct in 2011
* CEO says retaining its Russian market share is a must
* Beats fourth-quarter sales, profit forecasts
MOSCOW, Feb 22 (Reuters) - Yandex, Russia's most popular search engine, said it expects sales growth to slow this year as Russian Internet usage nears saturation, and will focus on defending its key market share after losing some ground to U.S. rival Google.
"Retaining the (Russian) market share is a must. As of today it is all right - we are not falling," Chief Executive Officer Arkady Volozh told a news conference.
Yandex, which raised $1.4 billion in an oversubscribed initial public offering (IPO) in New York last May, has seen its share of the Russian search market fall to just over 59 percent from 64 percent at the end of 2010, according to LiveInternet.
Although the market share loss is not expected to translate into any revenue losses, it is indicative of the company's ability to defend its leading position amid intensified competition with Google and local peers.
The company expects to achieve 40 to 45 percent revenue growth in full-year 2012, a slowdown from 60 percent last year, it said in a 2011 financial results statement.
"The slowdown is a natural process. The growth is now driven by increasing activity and not user numbers," said Yandex chief financial officer Alexander Shulgin.
He added the company would spend 18-20 percent of revenue on capital expenditures this year against 28 percent rate in 2011.
Full-year 2011 revenue grew 60 percent to 20 billion roubles ($672.30 million), Yandex said, with fourth-quarter sales rising 56 percent to 6.44 billion roubles and beating a 6.32 billion rouble forecast in a Reuters poll.
Quarterly net income, adjusted for stock based compensation expenses, rose 50 percent to 2.198 billion roubles, above a 2.14 billion rouble forecast.
Adjusted earnings before interest, taxation, depreciation and amortisation (EBITDA) increased 48 percent to 3.27 billion roubles for the EBITDA margin of 50.8 percent.