Of the many failures that shaped the life of healthcare entrepreneur Dennis Bastas, one of the most significant was early in his career during the dotcom bust of 2000. He was the president of a tiny internet company that went under, and it taught him about the risks of having too much exposure to one product.

Ever since, he’s preferred platform-based businesses, where the risk is diffused over many products. Now, as co-founder, chief executive and chairman of Arrotex Pharmaceuticals – the nation’s largest privately held generic drug supplier which reached $1.2 billion in sales last financial year – Bastas makes his debut at No. 139 on the Financial Review Rich List. He has a net wealth estimated at $990 million.