Warren Buffett's Berkshire Hathaway has sold $100 billion in Apple stock, increasing its cash balance to a record $325.2 billion.Berkshire Hathaway did not repurchase any company shares during the period and has been de-risking its balance sheet.Buffett remains critical of Bitcoin, but institutional adoption of Bitcoin ETFs has been growing rapidly.There is speculation whether Buffett will change his stance towards Bitcoin following its impressive performance.