Warren Buffett’s Berkshire Hathaway is nearing a deal to acquire Occidental Petroleum’s petrochemical business for about $10 billion, a person familiar with the matter said. It would be Berkshire’s largest deal since its acquisition of Alleghany in 2022 for $13.7 billion. Representatives for Occidental and Berkshire didn’t reply to messages seeking comment. Wall Street Journal first reported on the potential deal.After years spent refraining from large deals and progressively unwinding big holdings like his stake in Apple, Buffett appears to be back on the offensive. The 95-year-old CEO, set to leave that role at the end of the year, placed a $1.6-billion bet on UnitedHealth Group in recent months. Still, the conglomerate’s cash pile totaled $344 billion at the end of June, close to a record.