 At the time, the interest rate was 3.5. This meant Bob could generate $17,500 in annual income from the interest he earned, keeping his principal intact. That's $500 more a year than he actually wanted. So this was a good solution for Bob, at least until the bond matured. Now, when the 10 years was up, Bob had to reinvest his half a million. The problem? Interest rates had dropped to 1%. That meant