1. Understanding Interest Rates
Chapter 4

2. Present Value: Discounting the Future
Present Value (PV) - the value today of a payment promised in the future
A dollar paid to you one year from now is less valuable than a dollar paid to you today.

3. Discounting the Future (PV) First need to Understand Future Value (FV)
Let i = 0.10 (10 percent interest rate)
In one year: $100 +(.10 x $100) = $100 x (1+.10) = $110
In two years: $110+(.10 x $110) = $110 x (1+.10) = $121
OR $100 x (1+.10)2 = $121

4. Future value In three years: $121+(.10 x $121)= $121x(1+.10) = $133
OR $100 x (1+.10)3 = $133
In n years: FV = $100 x (1+ .10)n

5. Future Value
Future value in n years of an investment of PV today at interest rate i
(i is measured as a decimal, 10% = .10)
FVn = PV x (1+i)n
Calculate one plus the interest rate (measured as a decimal), raised to the nth power, multiply by the amount invested (present value PV).

6. Future Value
Note:
When computing Future Value, both n and i must be measured in same time units—if i is annual, then n must be in years.
The future value of $100 in 18 months at 5% annual interest rate is:
FV = 100 *(1+.05)1.5

7. Future Value
The future value of $100 in one month at a 5% annual interest rate is:
FV = $100 *(1+.05)1/12 = $
(1+.05)1/12 converts the annual interest rates to a monthly rate.
(1+.05)1/12 = , which converted to percentage is % or 0.41%(rounded)
Note: 0.05/12 =

8. Basis Point Faction of a percentage point is called basis point.
A basis point is one-one hundredth of a percentage point
One basis point (bp) = 0.01 percent.
On the previous slide: 0.41% is 41 basis points.

9. Discounting the Future PV Reverses the FV Calculation
FVn = PV x (1+i)n
PV = FVn /(1+i)n
In General:

10. Present Value

11. Present Value Example 1:
Present Value of $100 received in 5 years discounted at an interest rate of 8%.
PV = $100 / (1.08)5 = $68.05
Example2:
PV of $20,000 received 20 years from now discounted at 8% is:
PV = $20,000 / (1+0.08)20 = $20,000/ = $4,291
Discounted at 9%:
PV = $20,000 / (1+0.09)20 = $20,000/ = $3,568

12. Present Value Example3:
PV of $20,000 received 19 years from now discounted at 8% is:
PV = $20,000 / (1+0.08)19 = $20,000/ = $4,634
In general, present value is higher:
1. The higher the future value of the payment (CF).
2. The shorter the time period until payment (n).
3. The lower the interest rate. (i)

13. Mishkin Discusses Four Types of Credit Market Instruments
Simple Loan
Fixed Payment Loan (I will just mention this)
Coupon Bond
- Special case: consol bond
Discount Bond

14. We will focus on Bonds and look at three types of bonds
Coupon Bonds: which make periodic interest payments and repay the principal at maturity.
U.S. Treasury Bonds and most corporate bonds are coupon bonds.
Discount or Zero-coupon bonds: which promise a single future payment, such as a U.S. Treasury Bill.
Consols: which make periodic interest payments forever, never repaying the principal that was borrowed. (There aren’t many examples of these.)

15. Yield to Maturity -YTM
The interest rate that equates the present value (PV) of cash flow payments (CF) received from a debt instrument with its value today
Given values for PV, CF and n, solve for i.

16. Yield to Maturity - One Year Simple Loan

17. Fixed Payment Loan - YTM

18. Bond price is a present value calculation. YTM is the interest rate.
Bonds: Our Objectives
Bond price is a present value calculation.
YTM is the interest rate.
Supply and Demand determine the price of bonds.
- We will also discuss loanable funds and
money supply/money demand.
Explain why bonds are risky.

19. Coupon Bond Price
A simple contract-

20. Present Value of Coupon Payments
Price of a Coupon Bond
Present Value of Coupon Payments
Present Value of Principal Payment
Present Value of Coupon Bond (PB) =
Present Value of yearly coupon payments (C)
+ Present Value of the Face Value (FV),
where: i = interest rate and n = time to maturity

21. Example: Price of a n-year Coupon Bond
Coupon Payment (C) =$100, Face value (FV) = $1,000,
and n = time to maturity
Given values for i and n, we can determine the bond price PB
Definition: Coupon Payment / Face Value = Coupon Rate

22. Price of a 10-year Coupon Bond
If n = 10, i = 0.10, C = $100 and FV = $1000.
What’s the Coupon Rate?
Excel Example

23. Price of a 10-year Coupon Bond
If n = 10, i = 0.12, C = $100 and FV = $1000.
What’s the Coupon Rate?

24. YTM - Coupon Bond Suppose n = 10, PB = $950, C = $100 and FV = $1000.
What’s the Coupon Rate?
What’s the YTM?
YTM = or 10.85%

25. C = the coupon payment
FV = Face Value
P = Price
n = years to maturity

26. Using the Approximation Formula
Previous example:
n = 10, PB = $950, C = $100 and FV = $1000.

27. For our 10-year, $1000 FV bond with a $100 coupon payment selling at $950:
Coupon rate = 10%
YTM = 10.85%
App. YTM = 10.77%
Current Yield = 10.52%

28. Current Yield
Two Characteristics of Current Yield
Is a better approximation of yield to maturity, nearer price is to par (face value) and longer is maturity of bond
2. Change in current yield always signals change in same direction as yield to maturity

29. When the coupon bond is priced at its face value, the yield to maturity equals the coupon rate
The price of a coupon bond and the yield to maturity are negatively related
The yield to maturity is greater than the coupon rate when the bond price is below its face value

30. Consol – Special Case Coupon Bond
Infinite maturity
No face value.
Fixed coupon payment of C forever.
Pconsol = C/(1+i) + C/(1+i)2 + C/(1+i)3 + … + C/(1+i)t
As t goes to infinity this collapses to:
PConsol = C / i => i = C / P
$2,000 = $100/.05

31. Discount or Zero Coupon Bond
Definition: A discount bond is sold at some price P, and pays a larger amount (FV) after t years. There is no periodic interest payment.
Let P = price of the bond, i= interest rate, n = years to maturity, and FV = Face Value (the value at maturity):

32. Zero Coupon Bonds - Price
Examples: Assume i=4%
Price of a One-Year Treasury Bill with FV = $1,000:
Price of a Six-Month Treasury Bill with FV = $1,000:
Price of a 20-Year zero coupon bond at 8% and FV = $20,000:

33. YTM - Zero Coupon Bonds

34. Zero Coupon Bonds - YTM i = 1.0657 -1=> i =6.57%
For a discount bond with FV = $15,000 and P = $4,200, and n = 20, the interest rate (or yield to maturity) would be:
i = => i =6.57%
Note: This is the formula for compound annual rate of growth

35. Zero Coupon Bonds - YTM i = 1.06368 – 1 = .06368 or 6.368%
For a discount bond with FV = $10,000 and P = $6,491, and n = 7, the interest rate (or yield to maturity) would be:
i = – 1 = or 6.368%

36. From a Coupon Bond to Zero Coupon Bonds (called Strips)
Create n+1 discount bonds

38. Yield on a Discount Basis
SKIP

39. Distinction Between Interest Rates and Return

40. Holding Period Return
the return from holding a bond and selling it before maturity.
the holding period return can differ from the yield to maturity.

41. Holding Period Return Example:
You purchase a 10-year coupon bond, with a 10% coupon rate, at face value ($1000) and sell one year later.
Current Yield
Capital Gain

42. One year holding period return =
If the interest rate one year later is the same at 10%:
One year holding period return =
or 10.0%

43. Holding Period Return
If the interest rate one year later is lower, say at 8%:
One year holding period return =
or 22.5%
Where did the $1125 come from?

44. Holding Period Returns
If the interest rate in one year is higher at 12%:
One year holding period return =
or -.70%
Where did the $893 come from. You need to know how to calculate the $1125 and $893

46. Key Conclusions From Table 2
The return equals the yield to maturity (YTM) only if the holding period equals the time to maturity
A rise in interest rates is associated with a fall in bond prices, resulting in a capital loss if the holding period is less than the time to maturity
The more distant the maturity, the greater the percentage price change associated with an interest-rate change

47. Key Conclusions From Table 2
The more distant a bond’s maturity, the lower the rate of return that occurs as a result of an increase in the interest rate
Even if a bond has a substantial initial interest rate, its return can be negative if interest rates rise

48. Interest-Rate Risk
Change in bond price due to change in interest rate
Prices and returns for long-term bonds are more volatile than those for shorter-term bonds
There is no interest-rate risk for a bond whose time to maturity matches the holding period

49. Reinvestment (interest rate) Risk
If investor’s holding period exceeds the term to maturity
 proceeds from sale of bond are reinvested
at new interest rate
 the investor is exposed to
reinvestment risk
The investor benefits from rising interest rates, and suffers from falling interest rates

50. Real and Nominal Interest Rates
Nominal interest rate (i) makes no allowance for inflation
Real interest rate (r) is adjusted for changes in price level so it more accurately reflects the cost of borrowing
Ex ante real interest rate is adjusted for expected changes in the price level (πe)
Ex post real interest rate is adjusted for actual changes in the price level (π)

51. Real and Nominal Interest Rates
Fisher Equation:
i = r + πe
From this we get -
rex ante = i - πe
rex post = i - π

52. Inflation and Nominal Interest Rates
Mankiw

53. Inflation and Nominal Interest Rates

54. Real and Nominal Interest Rates
Real Interest Rate:
Interest rate that is adjusted for expected changes in the price level
r = i -πe
if i = 5% and πe = 3% then:
r = 5% - 3% = 2%
if i = 8% and πe = 10% then
r = 8% - 10% = -2%

56. A measure in inflationary expectations
i = r + πe
πe = i - r