Managing thousands of details and multiple risks for each of the multimillion-dollar houses he builds, he spent years rushing around with "one foot off the ground 20 hours a day, running the same scenarios through my mind time and time again, and being unable to put it aside, " says Mr. Weissensee, 58, of Mill Valley, Calif.

WSJ: When Stress Is Good for You

Both issues are likely to matter more as broking houses continue to shift from selling stocks and bonds, which produce only one-off transaction fees, to selling packaged financial products.

ECONOMIST: Wall Street