Decamillionaires are different from your basic affluent client according to Ekaterina Walsh, an analyst with Boston’s Forrester Research Inc.

Forrester defines the affluent as consumers with US$ 1 million or more in investable assets. Walsh says that within the affluent category, decamillionaires, consumers with more than US$10 million, stand out: These entrepreneurs become affluent younger, feel less secure about their wealth, and feel less confident about managing their assets on their own.

“Decamillionaires are a distinct breed,” she says. “Today’s über-affluent don’t fit the stereotype of stodgy old men who made their millions over a lifetime — they’re younger than the general affluent consumer, more likely to be female, and they achieve affluence relatively early thanks to their entrepreneurial activities.”

They average decamillionaire is only 57 years old, and has been affluent for 16 years. Yet, one in five decamillionaires doesn’t feel financially secure. “They’re constantly worried about their nest egg; they’re young and plan to retire at an earlier age than the less affluent. A pessimistic economic outlook compounds their money worries: Those with the highest investable assets are the least likely to say that the current recession will be followed by a prompt return to economic health.”

Almost half of decamillionaires say that they always seek investment advice from experts and rely heavily on their counsel.