The Chicago-based owner of the Los Angeles Times completed its sale of the newspaper on Wednesday in a surprise move that probably spells the end of its long-troubled relationship with Southern California’s leading news outlet.

The buyer is Patrick Soon-Shiong, a Los Angeles-area physician and a major shareholder of the paper’s former parent company, Tronc. Soon-Shiong is the billionaire founder and chief executive of NantHealth, based in Culver City. As part of the $500 million deal, he will also buy its sister newspaper, the San Diego Union-Tribune. News of the sale was first reported by The Washington Post on Tuesday afternoon.