Mogul Who Eyed Nasdaq in 2019 Is Now Kingpin of Italian Finance

Andrea Pignataro has quietly become one of the most important men in Italian finance, building a network of companies that control data, trade securities and help the European Central Bank manage the euro in an empire worth an estimated €25 billion ($27 billion).

The reclusive dealmaker from Bologna expanded in his home country after pursuing a bold plan to combine his ION Group with Nasdaq Inc. in 2019, according to people familiar with his operations. The talks, which haven’t been previously reported, ended without an agreement because of concerns about whether the New York-based exchange and Pignataro’s operations would fit together. But the aborted proposal ...