Berkshire Hathaway Inc.’s cash pile soared to $381.7 billion in the third quarter, a fresh record, and operating earnings at Chief Executive Officer Warren Buffett’s conglomerate surged 34%.  That figure hit $13.5 billion, driven by an increase in insurance underwriting profit, in a period that was marked by an unusually low disaster activity, according to filings published Saturday.Buffett offloaded $6.1 billion of shares during the period. In spite of that growing cash hoard, the firm’s net investment inc ...