Warren Buffett’s Berkshire Hathaway Inc. increased its stake in Wells Fargo & Co., building equity holdings amid a market decline that the billionaire investor said provided an opportunity for buying stocks “on sale,” Bloomberg reported. Buffett’s company added 9.7 million shares of the biggest U.S. home lender in the three months ended June 30, boosting its holdings by 2.8 percent. The increase in the Wells Fargo stake cost Berkshire about $277 million, assuming purchases came at the bank’s average trading price for the second quarter of $28.53 a share.