The latest paid-click figures for Google were up only 3.1 percent in February from a year earlier, possibly prompting a 3 percent drop in Google's stock.
The vast majority of Google's revenue is from people clicking on sponsored search listings.
Even though Google's paid-click growth rate was well below the fourth-quarter's 25 percent year-over-year growth, Google outperformed the market growth rate of 0.9 percent, JPMorgan analyst Imran Khan wrote in a research note citing ComScore figures. ComScore has not released the latest figures publicly, but has provided them to Wall Street analysts who pay a subscription fee.
Yahoo had 5.3 percent year-over-year growth in paid clicks in February and Microsoft's paid clicks declined 13.1 percent from the year earlier, according to Khan.
Last month when ComScore released the paid-click rate figures that showed flat-year-over-year growth for Google in January, the company's stock fell 8 percent the next day as Wall Street worried about slowed ad sales growth at the bellwether tech company.
Days later, ComScore explained that the drop in Google's paid click rate was due to "Google's own quality initiatives that result in a reduction in the number of paid listings" and said that the reduction in listings was "offset by paid revenue per click."
Earlier on Wednesday, Nielsen released figures that show Google's U.S. Web search market share rose in February to 58.7 percent, up slightly from January and the same period a year ago, while Yahoo's was down at 17.6 percent.