March 27 (Bloomberg) -- Google Inc. declined 3.1 percent in Nasdaq trading after a report showed slower growth in the number of people clicking on Internet advertisements in February, the second straight month of disappointing results.

Clicks on Google's sponsored links, four-line ads that mostly run next to search results, rose 3 percent to 515 million in February from a year earlier, researcher ComScore Inc. said yesterday. In January, Google had no growth, after a 25 percent increase in the fourth quarter.

The slump signals the slowing U.S. economy may cut into sales and hinder Google in meeting projections for the first quarter, analysts at Citigroup Inc. and UBS AG said. Google, the world's most popular Internet search engine, got about 99 percent of its $16.6 billion in sales last year from online ads.

``The numbers are soft again,'' said Stanford Group Co.'s Clayton Moran, who rates the stock ``hold.'' ``We think the slowing of growth is due to the economy,'' heightening investors' concern a stumbling housing market and a possible recession may curb online shopping, the Boca Raton, Florida-based analyst said.

Lehman Brothers also cut estimates on Google for the period and reduced its price target for the stock to $580 from $644. Google, based in Mountain View, California, dropped $14.11 to $444.08 at 4 p.m. New York time on the Nasdaq Stock Market. The stock has tumbled 36 percent this year.

Little Improvement

``February data from ComScore suggests that Google's paid click volumes in the U.S. aren't getting meaningfully better,'' UBS's Benjamin Schachter said in a report. The New York-based analyst, who advises investors to buy the shares, cautioned that historically, ComScore's paid clicks haven't ``correlated accurately'' with his firm's Google sales estimates.

Ad clicks fell 3 percent in February from the previous month, Reston, Virginia-based ComScore said. In January, clicks fell 7.5 percent to 532 million from the previous month.

Google spokesman Brandon McCormick declined to comment.

Google has upgraded its systems to eliminate promotions that aren't relevant to searches, product manager Nick Fox said last month. That makes people more likely to click on ads even though a fewer number are shown on users' screens, he said in a Feb. 28 interview.

ComScore, in a blog posting the following day, said eliminating less-relevant ads will benefit Google.

``In the long run, this should increase relevancy and therefore make it an even more efficient ad format, which would raise prices,'' Moran said. ``In the short term, it looks like it's having a negative impact.''

In January, Google reported fourth-quarter profit and revenue that missed analysts' estimates. The company also said it failed to make as much headway as expected selling ads on social- networking sites such as News Corp.'s MySpace.

To contact the reporter on this story: Ari Levy in San Francisco at alevy5@bloomberg.net

Last Updated: March 27, 2008 16:10 EDT