Despite the big marketing and advertising push Microsoft has given Bing, the new search engine failed to gain much ground among users in September, while Google increased its dominance, according to comScore.
Bing's share of US search queries rose slightly from 9.3 percent in August to 9.4 percent last month, while Google, out alone in first place, increased its share from 64.6 percent to 64.9 percent, comScore said.
Yahoo took a small tumble, as its share of queries fell by half of a percentage point to 18.8 percent, leaving it in a distant second place.
Overall, US internet users ran 13.8 billion searches in September, 1 percent less than in August.
Since Bing's introduction in late May, search industry experts have been watching intently to see how much headway Microsoft makes in a market where it hasn't enjoyed as much success as it has hoped to.
Bing has certainly improved Microsoft's market share, which stood at 8.4 percent in June, but not in a radical fashion, especially considering that Microsoft is reportedly spending about $100 million to promote the search engine.
The consensus among experts has been that while Bing is better than its Live Search predecessor, it doesn't offer revolutionary innovations in search technology.
Bing will certainly get a big, if artificial, boost when and if the search deal that Microsoft and Yahoo signed in July gets approved by regulators. However, even if that clearance is granted, the deal could take up to two years to fully implement, the companies have said.
The deal calls for Yahoo to turn off its back-end search infrastructure and rely instead on Bing for website crawling and indexing. The 10-year search deal also stipulates that Yahoo will sell premium search-advertising services on behalf of both companies, while Microsoft handles text-based, pay-per-click search ads.