Carl Icahn is doubling down on Yahoo.

The billionaire investor and Yahoo board member has acquired about 6.8 million more shares through entities he controls, according to government filings.

That brings his total Yahoo holdings to 75.6 million shares, or about 5.4 percent of shares outstanding. The newly acquired shares were bought in a series of transactions on Monday, Tuesday and Wednesday at prices ranging from $9.80 to $10.

On the news, shares of Yahoo climbed $.30, or 2.8 percent, to $10.88 in late morning trading Friday, about 60 percent off their 52-week high.

Mr. Icahn gained board seats for himself and two allies last summer after agreeing to halt a proxy battle to oust the incumbent directors. He was a vocal proponent of an acquisition proposal by Microsoft, which bid $31 per share for Yahoo on February 1.

After months of maneuvering, Microsoft abandoned the chase in June. Earlier this month, Microsoft Chief Executive Steve Ballmer restated his position that the company no longer is interested in acquiring Yahoo, but might be interested in a deal involving its online search operations.

Yahoo is conducting a search for a new chief executive after founder Jerry Yang’s announcement November 17 that he would be stepping down to resume his role as chief Yahoo.

The Internet company has struggled to reignite growth amid stiff competition for Internet advertising from Google and Microsoft.

In October, Yahoo’s U.S. search share was 20.5 percent, an increase of .3 percentage points from September, according to comScore. That put Yahoo in distant second place behind Google, with 63.1 percent, an increase of .2 percentage points. Third place Microsoft was flat at 8.5 percent.