Week 9 Flashcards
Malkiel’s rules
- There is an inverse relationship between bond prices and yields;
- A decrease in a bond’s yield to maturity causes a larger change in the bond’s price than an increase in yield of the same size does;
- The prices of long-term bonds exhibit greater sensitivity to interest rate movements than those of short-term bonds;
- Although the sensitivity of bond prices to yield changes rises with their maturities, it does so at a decreasing rate;
- There is a negative relationship between the sensitivity of bond prices to interest rate changes and the rate at which they pay coupons; and,
Homer and Liebowitz
Bonds with higher yields to maturity are less sensitive to changes in yield than bonds with lower yields to maturity.
Duration is an important tool when managing a bond portfolio because
in addition to measuring the effective average maturity of the portfolio, it:
Indicates how sensitive a portfolio is to changes in interest rates; and
Can be used as a tool in immunising the portfolio against interest rate risk.
Rule 1 for Duration
A zero-coupon bond has a duration equal to its maturity;
Rule 2 for Duration
A bond’s duration is lower when the coupon is higher
This is because, as the coupon rate rises, so too do the weightings on the bond’s earlier coupons and, therefore, the weighted average maturity of all the bond’s cash flows falls
Rule 3 for Duration
a bond’s duration increases with its time to maturity
duration always increaese with maturity for bonds selling at par or at a premium to par
Rule 4 for duration
the duration of a coupon bond is higher when the bond’s yield to maturity is lower
This is because, as the bond’s yield increases, a larger proportion of the total value of the bond lies in its earlier payments, reducing its effective maturity;
RUle 5
The duration of a level perpetuity is (1+y)/y, showing that an instrument’s maturity and duration can be materially different;
while duration is a good approximation for
while duration is a good approximation for small yield changes, it is less so for larger changes
b/c relationship between the percentage change in the price of a bond against the change in its yield is not linear
investors view convexity as an attractive characteristic of bonds. More specifically:
Bonds exhibiting greater curvature in the price- yield curve enjoy greater price gains when yields fall than they suffer price falls when yields rise; but,
Investors view convexity as an attractive characteristic of bonds but
investors will need to pay a higher price and accept lower yields to maturity on bonds with greater convexity
connvexity concepts for callable bonds.
When interest rates are high
the price-yield curve is convex in the way it is for straight bonds. More formally, the curve exhibits positive convexity, or the price-yield curve sits above its tangency line;
connvexity concepts for callable bonds.
When interest rates are low
the price-yield curve exhibits negative convexity, or an area where the price-yield curve falls below its tangency line;
connvexity concepts for callable bonds.
The negative convexity of part of the price-yield curve is
a result of the face the bond cannot have a value greater than its call price, or it being subject to price compression as yields fall.
Duration and convexity of callable bonds
as rates fall, we sometimes say the bond is
subject to a price compression - its value is compressed to the call price (bond cannot be worth more than the call price)
Duration and convexity for callable bonds
Indeed, negative convexity is unattractive to investors, as
it indicates that price falls for a given interest rate rise will be greater than price rises for equivalent rate rises. This is a result of the bond issuer having the choice of calling the bond back