The search engine wars are still on, and while Microsoft is seeing an uptick in its search share…it mostly seems to come at the expense of partner Yahoo.

Microsoft has been working hard to raise its share of the Internet search market, aggressively promoting its Bing search engine and striking a ten-year deal with Yahoo to have Bing power Yahoo searches. And the latest search engine share numbers from media analysis firm Comscore suggest some of that effort is paying off, with Microsoft sites showing the greatest month-to-month increase in the industry. However, the growth doesn’t seem to be slowing Google; in fact, it seems to mostly be coming at the expense of new-partner Yahoo.

Comscore’s latest rankings cover U.S. Internet users for November 2009; according to the figures, Microsoft sites (including Bing) saw a 0.4 percent increase compared to October 2009, jumping to a 10.3 percent share of the U.S. search market. However, Yahoo sites saw a 0.5 decline during the same period, dropping from an even 18 percent of the market in October to 17.5 percent in November.

Read More: Digital Trends