(Bloomberg) -- Warren Buffett can cause executives angst when he invests in their companies.Most Read from BloombergTraders Line Up for ‘Once-in-a-Generation’ Emerging Markets BetBlackstone Is Building a $25 Billion Empire of Power-Hungry Data CentersTrump Cash Stockpile at Risk From $450 Million Dual VerdictsMusk Says First Human Patient Has Received Brain ImplantAmazon Drops iRobot Deal; Roomba Maker Cuts 31% of StaffJapan’s trading firms illustrate this point. Berkshire Hathaway Inc. bought s