On Friday, shares of information technology stalwart IBM Corp. (IBM Quick QuoteIBM - Free Report) are sliding, down about 2.5% in early morning trading—the stock was down about 3.4% in premarket trading—after Warren Buffett said he’s sold about a third of his stake in the company.

Telling CNBC, Buffett, who is IBM’s largest shareholder through his company Berkshire Hathaway (BRK.A Quick QuoteBRK.A - Free Report) , said he has sold roughly a third of his 81 million shares in the company, and he starting selling once the company’s price rose above $180 a share.

"I don't value IBM the same way that I did six years ago when I started buying," he said. "I think if you look back at what they were projecting and how they thought the business would develop, I would say what they've run into is some pretty tough competitors,” said Buffett.

Berkshire will still own about 50 million IBM shares, and the tech company will still be one of Berkshire’s largest holdings, behind only Kraft Heinz (KHC Quick QuoteKHC - Free Report) , Wells Fargo (WFC Quick QuoteWFC - Free Report) , Coca-Cola (KO Quick QuoteKO - Free Report) , and American Express (AXP Quick QuoteAXP - Free Report) .

Year-to-date, IBM has lost about 4.18% in value, and its last quarterly earnings report showed that the company’s revenues have fallen for 20 straight quarters in a row. Big, flashier names in cloud computing, particularly Amazon’s (AMZN Quick QuoteAMZN - Free Report) Amazon Web Services, have overshadowed companies and businesses like IBM, who are more server-focused.  

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