Q. I have an ad from a financial institution that promises 4.06% APY interest for a six-month CD. It states: "...promotional incentives included to obtain yield. Certain restrictions apply." Can you imagine what incentives they're talking about? Perhaps requiring that I open a checking account, credit card, something like that?

A. There isn't an FDIC-insured bank in the world paying 4% on a six-month CD right now.

What you've seen is one of many eye-catching ads insurance agents are running all across the country as a marketing gimmick to sell annuities.

To obtain those above-market rates, you usually have to go to the agent's office and listen to a sales pitch.

Buy an annuity, and you can buy one of the lucrative CDs.

Customers write a check to an FDIC-insured bank, which the insurance agent uses to buy a CD. So the principal is guaranteed, just as the ads usually promise.

Of course, that CD also is paying far less than the ad promised.

The insurance agent makes up the difference from the substantial fees he's paid for selling the annuity. That's what the fine print means when it says: "Promotional incentives included to obtain yield."

While the agents usually say you don't have to buy an annuity to buy a CD, the ads usually contain another clause that says something like: "Yield and deposit amount subject to availability." Or, in your case, "certain restrictions apply."

So don't be surprised if the great CD rate that got you in the door turns out to be unavailable if you don't buy some sort of insurance.