Google shares below $300 for first time since 2005

SAN FRANCISCO (Reuters) - Shares of Google Inc on Wednesday fell below $300 for the first time since late 2005 after analysts lowered their estimates on the Internet search giant, citing a weak advertising market.

The shares were down 6.5 percent at $291.19 in afternoon Nasdaq trade. The stock is off more than 50 percent this year.

The global economic slowdown is impacting many companies' advertising budgets, hurting Google's main business, paid search ads.

Citigroup analyst Mark Mahaney said in a note that the online advertising growth rate is likely to slow in the fourth quarter for top e-commerce companies such as eBay Inc and Amazon.com Inc. The slowdown will likely impact Google, he said.

Mahaney cut his fourth-quarter earnings and net revenue forecasts for Google by 3 percent, to $5.03 a share and $4.16 billion, respectively. He lowered his 2009 earnings and net revenue forecasts by 5 percent, to $21.18 a share and $17.46 billion.

Analysts, on average, expect Google to earn $5.10 a share for the fourth quarter and $22.39 a share for 2009, according to Reuters Estimates.

Collins Stewart analyst Sandeep Aggarwal lowered his outlook on Google for the fourth-quarter and 2009, citing further weakening in the retail and advertising sectors.

"We believe that the high CPC (costs-per-click) inflation Google has been experiencing for the past six quarters is not sustainable and will pressure core search growth" in the fourth quarter and 2009, Aggarwal said in a note.

(Reporting by Gabriel Madway; editing by John Wallace)