In 2005, Mori Arkin sold Agis, his family's pharmaceutical firm, to U.S. based Perrigo (PRGO) for $390 million. At the time, he only took half the money in cash; the rest came in the form of Perrigo stock. If he had held onto the stock, it would be worth about $1 billion today. Instead, Arkin diversified, a path that led him to a fortune that, as of this year, is worth ... well, about $1 billion. Either way, Arkin is now one of 18 billionaires in Israel.