Warren Buffett on Saturday applauded Apple Inc.'s share repurchase program, noting that as shares are bought back, Berkshire Hathaway's stake grows on its own. Apple, which was already an aggressive purchaser of its own shares, announced a $100 billion buyback program earlier this week. Buffett on Friday revealed that Berkshire had added 75 million Apple shares to its portfolio in the first quarter, building on an already sizable stake.