Berkshire Hathaway sold a portion of U.S. Bancorp , a bank stock that the conglomerate has held since late 2007, a regulatory filing with the Securities and Exchange Commission showed. The conglomerate reported owning 52.5 million shares of U.S. Bancorp as of Oct. 31, roughly 3.5% of the bank’s outstanding shares, the filing showed. That’s down from a stake of 137.4 million shares, including 17.6 million held by its New England Asset Management subsidiary, as of the end of the second quarter on June 30. The filing indicates that Berkshire has sold 84.9 million shares, currently valued at $3.8 billion. The sale was prompted by Berkshire’s stake falling below 5%, the filing stated. The filing also showed that Buffett himself owns almost 499,000 shares in his personal accounts. Buffett first bought 23.3 million shares of U.S. Bancorp in the fourth quarter of 2007 . Shares of U.S. Bancorp are down about 20% this year, compared to a roughly 17% loss for the S & P 500. Berkshire started unloading its bank stocks this year, exiting positions in JPMorgan, Goldman and Wells Fargo. The conglomerate still owned a sizable stake in Bank of New York Mellon at the end of the second quarter.