According to a report published by Marin Software Wednesday. The report, “Why the Search Alliance Is Paying Off for Paid Search,” suggests the Microsoft and Yahoo search alliance increased the share of paid-search impressions by 4% and share of clicks by 2%, while Google’s share declined by the same percentage.

Microsoft and Yahoo saw paid-search share of impressions rise from 19% to 23%, and paid clicks rise to from 19% to 21% in the first few months after the alliance went into effect.

Matt Lawson, Marin’s marketing vice president, said in the report that he sees the drop in Google’s ad share as an opportunity for marketers to take advantage of Bing and Yahoo. “We know Bing can potentially close the gap, as advertisers come on or rejoin the new platform,” he says.

“The search alliance has resulted in improved traffic quality for advertisers. Higher conversion rates demonstrate improvements. Excluding the impact of seasonality, conversion rates rose by 12% during the study period. The results show that consumers respond to the combined platform.”

The study also found that the amount marketers spent on Google rose 60%, whereas spend on a combined Yahoo and Bing increased by 44%.

The study also looked at post-click conversions and to assess traffic quality.

Marin’s study concluded that conversion rates on the search alliance became more favorable following the transition. Marin attributes this to several factors including higher-quality traffic, better targeting options and a more efficient marketplace.

Marin’s study, run between Aug. 15 and Dec. 15, 2010, analyzes data from more than 800 of its clients that collectively manage more than $1.8 billion in annual paid-search spend.