The parent company of The San Diego Union-Tribune announced this morning that it has reached an agreement to sell the newspaper to the Beverly Hills private equity firm Platinum Equity for an undisclosed price. The LA Times says Platinum specializes in buying businesses in struggling markets and has completed nearly 100 acquisitions in a range of industries since being founded in 1995. With a daily circulation of 296,000, the U-T is the third largest newspaper in California, behind the LA Times and SF Chron.