Sept. 21 1999 11:37 PM

Although the probabilities that various candidates running for the same office will win should add up to 100 percent, the stock prices in the Iowa market don't necessarily add up to $1. That's because an investor who buys Candidate A's stock doesn't necessarily know or care how much another investor is paying at that moment for Candidate B's stock. So while Bradley's stock has risen steadily since Sept. 4, Gore's has fluctuated. Since Sunday--after Gore's stock had plunged six cents--shares in each candidate have gained two cents, pushing their combined price above $1. One or the other must give way. Over the next couple of days, we'll find out which.