Bonds have traditionally been considered a “safe” investment suitable for retirees and other investors with low risk tolerance. However, a bond fund does not behave in exactly the same way as an individual bond. Investing in a bond “fund”differs in several crucial ways from investing in a bond, and investors need to understand that difference.
Standard convention for asset mixes
The standard convention in investing is to have some amount of your investment portfolio in Fixed Income Assets because they are “safer” (i.e., less risky). Depending on your age and risk tolerance you are told by professionals like me to invest as much as 70% of your retirement account in this asset class. Most people have this part of their portfolio in bond funds which are one of ten mutual fund choices typically offered in a 401K Plan. Since bonds offer a pre-determined rate of return and stocks do not, risk-averse folks generally put their money here. Makes sense right? Indeed it does, but only when interest rates are declining. Unfortunately, what you don’t hear much about is what happens to bond fund values in a rising interest rate environment. When interest rates rise, bond funds lose money. In fact, Vanguard tells you this in the Product Summary section of its Long-Term Bond Index Fund. They say, “Long-term bonds tend to be very sensitive to interest-rate changes, one of the fund’s key risks is that increases in interest rates may reduce the price of the bonds in the portfolio, which would reduce the fund’s share price”.
Think of it this way
To understand why this is, you first need to know a little bit about bonds. Normally this is where your eyes glaze over and you say to yourself, “Oh not bonds, I’ve tried and tried, but I never really ‘got’ bonds.” Well, here’s a different angle on the concept that might just click with you.
In its simplest form, understanding what happens to bond prices when interest rates rise or fall comes down to a simple mathematical equation where you only have to solve for one unknown. There are three factors in the problem:
A, the bond’s price