Data firm StatCounter said Monday that though Google remains the leader in the search field, its share took a battering in January, dropping a 2 percentage points in as many months to 74.8 percent of US search referrals.
In a long and distant second place, Microsoft's Bing was recorded at 12.4 percent, followed by Yahoo at 10.9 percent -- with both shares rising month-on-month.
StatCounter chief executive Aodhan Cullen said in prepared remarks it will be "fascinating" to see if these gains continue, after speculation that Yahoo and Bing's gains would be wiped out if users switched back to Google.
The data firm said it is "only Firefox users responsible" for the change in US search share.
"This highlights the importance of the default search option and the significance of the upcoming Safari search deal for the major players," Cullen said.
Mozilla, the maker of popular browser Firefox, switched its primary search engine from Google to Yahoo (which is powered by Bing), late last year. The deal will expire in five years.
Firefox users generated about 14 percent of US internet usage in January, according to the company.