Managing director, Dyson
Net worth: $4.4 billion
When were you last underestimated?
When I had the idea for the vacuum cleaner, my first thought was to sell my technology to other companies. I did that for a few years, but it was deeply unsatisfactory. So I thought, well, I must make it myself. I went to people who supplied money—venture capitalists, equity funds, banks. And none of them would back me. Two explicitly said it was because I was an engineer. I said, “But why can’t an engineer or designer run a business? They probably know more about the product, how it’s made, and who is likely to buy it than anyone else.” So of course they kicked me out the door. I ended up going to a clearing bank and borrowing money, over a million and a half dollars. It was a very risky thing to do. But I retained all the equity in my company. And I’m very glad I did.