OMAHA, NEB.—  Warren Buffett's company Berkshire Hathaway’s ownership of HP Inc. has almost drop below 10% after it sold nearly 5 million shares, according to a regulatory filing. Berkshire owned more than 12% of HP’s stock before it started to trim its stake last month. Now it’s down to 10.2% after several stock sales of HP. Berkshire amassed its HP stake early last year. Even after the latest sales, Buffett’s, Nebraska-based conglomerate still held more than 100.9 million shares. Altogether, Berkshire has sold just over 20 million shares in the past month. In the past 30 days, shares of HP Inc. have tumbled nearly 14%, even with a broad sell-off across the tech sector. Shares of Apple Inc. have fallen 9%. But HP is still one of the biggest decliners among peers. Why Warren Buffett has beeb sell HP shares is not know. Many investors watch Buffett’s moves closely because of his extremely successful track record over the years.