Chapter 5: The Structure of Interest Rates 47
than today’s market interest rate because that would mean that the bond
had more capital gains. We could adjust the present-value formula for
As an example, consider three bonds, A, B, and C, all issued within a short
period. Bond A pays interest of $20 each year for two years and repays
the principal of $1,000 at the end of the two years; it is issued when the
market interest rate is 2 percent. Bond B is issued just a bit later when the
market interest rate suddenly and unexpectedly rises to 8 percent, so
bond B pays interest of $80 each year for two years and repays the
principal of $1,000 at the end of the two years. Bond C is issued just a bit
later when the market interest rate suddenly and unexpectedly falls to 5
percent, so Bond C pays interest of $50 each year for two years and
repays the principal of $1,000 at the end of the two years. The market
interest rate is now expected to remain at 5 percent for the next two
years.
First, we can use the present-value formula, without adjusting for taxes:
Now, consider an investor who has a capital-gains tax rate of 20 percent
but a tax rate on interest income of 35 percent. Suppose that the prices of
the three bonds were based on the before-tax present-value formula, as
shown above: $944.22 for bond A, $1,055.78 for bond B, and $1,000.00
for bond C. Then, we could calculate the investor’s after-tax yield to
maturity for each bond by using those prices and using the after-tax
income in the numerator of the present-value formula:
Bond A: …