The Series 65/66 exams don't like to give you a lot of questions that prove only that you've memorized something. You'd never know that from attending many of the live classes across the country, but, I assure you--it's true. NASAA doesn't like a lot of memorization. For example, you don't get to simply memorize "ADR = foreign stock, domestic market." You have to tell them how an American holding an ADR would be affected if the US dollar depreciates relative to the foreign currency. Similarly, you can't just memorize that zero-coupon bonds have "high duration" or a lot of interest rate risk. You have to know that much in order to think outside the box and apply that knowledge on a fun question like this:
If an investor purchases a 10-year US Government zero coupon bond that he plans to hold to maturity, the most important investment risk is
A. market risk
B. interest rate risk
C. purchasing power risk
D. reinvestment risk
EXPLANATION: zero coupon bonds have no reinvestment risk because there is no cash flow coming in every six months to reinvest at varying rates. Eliminate that choice. Market risk is always a problem because investors can definitely panic like a herd of buffalo--but the question says he's going to hold the thing until maturity. What does he really care about the market price if he isn't going to sell? Doesn't that also eliminate "interest rate risk," which sends the market price down when rates rise, but, again, he has no plans to sell? Yes. I think. I mean, at least I have some pretty solid reasons to eliminate those two answer choices. Can I eliminate "purchasing power risk"? No--he's locked into a fixed rate of return over 10 years. Who know where inflation will be?
That's the type of thinking you'll have to do on the exam. You won't know for sure if you're on the right path. Your job is to see if you can eliminate answer choices until you get down to the one you can't eliminate. That one is the right answer.