Warren Buffett's Berkshire Hathaway reveals major stake in HP, tech stock soars
Berkshire purchased nearly 121 million shares of HP, according to securities filings. That stake was worth roughly $4.2 billion based on Wednesday's closing price for the stock, amounting to a holding of about 11%.

Warren Buffett's Berkshire Hathaway has initiated a major stake in tech hardware stock HP Inc. , becoming the largest shareholder in the PC and printer maker.

After largely sitting on the sidelines in the early days of the Covid pandemic, Berkshire has become more active in recent months. The conglomerate announced a deal to buy insurance company Alleghany for $11.6 billion last month and has been scooping up shares of energy stock Occidental Petroleum.

HP, a leading name in personal computers, has lagged badly behind larger tech names over the past decade and beyond. Before the Berkshire news, the stock had gained less than 50% since October 2009.

"We view Berkshire buying HPQ shares as a positive that validates HPQ's strategy/deep value," wrote Evercore ISI tech analyst Amit Daryanani in a note.

HP joins elite company among rare tech holdings for Buffett, who has famously avoided most stocks in the sector for not fitting his value investing style. Apple is Berkshire's single biggest outside holding and one of Buffett's best investments ever, reaping billions for Berkshire since the conglomerate started buying in 2016.

— With reporting by CNBC's Michael Bloom.