Microsoft Corp's Bing search engine won more market share from rivals last week, according to new industry data released on Wednesday, but still trails Google Inc and Yahoo Inc, Reuters reported.
Challenging market leader Google -- which in turn is looking to break into Microsoft's core software market -- is a long-term project, said Microsoft chief executive Steve Ballmer.
"We have had some very good initial response," Ballmer said at a conference in Detroit. "I don't want to over-set expectations. We are going to have to be tenacious and keep up the pace of innovation over a long period of time."
Microsoft grabbed 12.1 percent of U.S. Internet searches for the work week June 8-12, according to data released by industry tracker comScore earlier on Wednesday.
That is up from 11.3 percent in the June 1-5 period -- the week in which Bing was launched -- and up from 9.1 percent the week before that.
For comparison, Google got 65 percent of U.S. searches in May, the last full month for which figures are available, followed by Yahoo with 20.1 percent and Microsoft with 8 percent.
Analysts and investors are keenly awaiting data for all of June to see if Microsoft can hold onto early gains.