Yahoo Inc board member Carl Icahn has cut back his stake in Yahoo, selling nearly 13 million shares since last Thursday, according to a regulatory filing on Monday.

Icahn Capital reported that the overall Yahoo stake held by various Icahn-related funds was 4.48 percent, down from 5.38 percent as of June 30, according to Reuters data.

Icahn's stock sales come one month after Yahoo struck a deal to outsource its search technology to Microsoft Corp , a partnership Icahn advocated.

Since the deal was announced, Yahoo's stock price has declined nearly 16 percent, closing Monday at $14.49.

According to Monday's filing, Icahn remained optimistic about Yahoo's long-term prospects.

Icahn sold his Yahoo shares to better balance his portfolio of tech stocks and because the window for Yahoo directors and offices to sell stock would be closing after August 31, according to the filing.

The reporting persons continue to believe in the wisdom of the Microsoft-Yahoo search transaction and fully support the performance of the Issuer's CEO Carol Bartz, Icahn Capital said in its filing.

According to the filing, Icahn sold his Yahoo shares between August 27 and August 31 at prices ranging from $14.75 to $14.92.

Icahn amassed the bulk of his stake in May of 2008, according to media reports at the time, when shares of the company were trading in the low- to mid-$20 range.

(Reporting by Alexei Oreskovic; editing by Carol Bishopric)

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