The wealthiest newcomers to the Forbes 400 list include entrepreneurs who took their companies public barely after founding them. To a large degree, the vast wealth generated by a few technology entrepreneurs is a result of investors' increased willingness to put money into emerging technologies. Investors in recent years have grown more willing to risk money in firms with a minimal financial track record, Geist said.
Stock is by far the paramount asset of the new economy's ultra-rich.
A look at the top of the rankings drives home the point. Of course, there's a flip side as well. While a lucrative IPO can generate a fortune for a company founder, a stock downturn can erase those gains rather quickly, Edwards said. Another thing to note about stock is that it's not always easy to cash in. Although a person who owns a small number of shares in a company can easily exchange stock for cash on any trading day, the same is not true for large shareholders.