PARIS/AMSTERDAM—Vincent Bollore is set to own $7 billion worth of Universal Music Group shares after it floats next week, raising questions about how the French tycoon could use this new source of cash as Universal’s parent Vivendi charts a new course. Bollore, the top investor in Vivendi who spearheaded the spin-off of the world’s biggest music label, is set to be one of the deal’s biggest winners, the prospectus issued on Tuesday showed. Listing Universal, with an estimated equity value of 33 billion euros ($39 billion), involves distributing 60 percent of its shares to Vivendi’s shareholders. Bollore is set to receive about 18 percent, worth about 5.9 billion euros ($7 billion). “The question next is what he will do with his share,” a source familiar with the transaction said. “The cash that he will get from this, he could deploy it in some other way.” Universal’s listing, Europe’s biggest so …