St. Paul Travelers ( STA) reportedly is in discussions about a merger with Zurich Financial, in what could create a global insurance titan to compete with American International Group ( AIG). The talks are preliminary and could break down, and the transatlantic transaction could face insurmountable regulatory hurdles, the Wall Street Journal reported Friday. St. Paul's market capitalization is about $30 billion, about $3 billion less than Zurich, whose shares rose in European trading after the talks were reported. On a total asset basis, Zurich, with about $340 billion, dwarfs St. Paul, which has about $113 billion. The companies did about $90 billion in revenue last year. By comparison, AIG does about $100 billion in annual revenue. St. Paul shares closed at $42.96 Friday, down about 3% this year.