MangoMan wrote:doesn't the lost opportunity of investing in higher rate bonds as interest rates increase basically offset the equivalent loss in a bond fund? You may not lose principal if you don't sell, but you will be collecting a lower coupon than if you sold and reinvested at the higher rate. Isn't that what duration is all about? Please clarify if I am wrong.
No, if I understand what you're saying, you are correct. But note that if you have an individual bond, which you sell in order to buy a higher coupon bond of the same type/rating, you will lose. The bond market is liquid enough that the bond you sell would be discounted to provide the same return to the new owner as the bond you would buy, and discounted a little bit more to provide profit in the transaction (bid/ask spread). Unless you need cash or are trying to change your investment in some way other than simple yield increase, it is better to sit tight.
The point is with an individual bond you get to weigh the merits and make a decision.
With a bond fund you have the manager making decisions (either discretionary or being forced by the focus of the fund) and you have a whole bunch of other investors forcing the fund manager to buy or sell. What happens is that investors want out of the fund, so the fund manager has to sell bonds to raise cash. Or the investors want into the fund so the manager has to buy bonds. Investor psychology being what it is, it seems these events happen opposite when they should happen for best investment results. Either way, the effect is that in a rising rate environment, bond funds have a strong bias to losing more money than individual bonds. And since rates are never 100% steady but tend to oscillate around their current trend line, a bond fund tends to lose a bit of capital frequently when rates bump up, and not gain it all back when rates drop. An investor holding individual bonds would never notice or suffer any effect from that minor oscillation.
Why own a bond fund then? It is a lot easier. Also a diversified fund has lower risk of default by any one issuer causing significant harm, so unless you can spread your bond dollars among 20+ issuers, be cautious of the default risk in buying individual bonds. (Obviously for individual U.S. treasuries and U.S. treasury funds, there is change in default risk because those funds are not diversified.)
Edit: that last line should read "...is NO change in default risk...". And earlier in addition to the line regarding bid/ask spread, also consider the commissions you pay to sell one bond and buy another.