Macaulay Duration Formula
sigma(time*PVcashflows)/PV of cashflows Value-weighted time average
Modified Duration
Dmod = v_ -1/P (dP/di) = v (t1Rv^t1 + … + tnRv^tn)/(Rv^t1 + … + Rv^tn)
Volatility
v_ = -1/P (dP/di) = d_ / (1 + i) = d_v
Annuity equation for d bar
(Ia)n]i / an]i
Duration for a zero coupon bond that pays in n years
d_ = n
D bar as an equation for force of interest
(-1/P)(dP/d&) = d_
Macaulay Convexity as force of interest
(1/P)(d^2P/d&^2) = d_
Modified Convexity
(1/P)(d^2P/di^2) = v^2[Cmac + Dmac]
Forward Rates
Spot rates: a(1) = 1.06, a(2) = (1.07^2), a(3) = (1.08^3)
f[1,2] = one forward rate deferred 1 year a(2)/a(1)
time 2 –> 3 a(3)/a(2) = 1 + f[2,3]
time 1 –> 3 a(3)/a(1) = (1 + f[1,3])^2
Immunization (Full and Reddington)
PVassets = PVliabilities Dmacassets = Dmacliabilities
Reddington Immunization
Asset convexity > liability convexity, asset convex has to be more curvy
Variance/Convexity and Expected Value/Duration
Variance acts like convexity, and expected value acts like duration
Higher convexity and Lower convexity
Bonds and lump sum
Immunization overkill
Match cashflows assets + liabilities move together
Basic Immunization
Match value at i, match duration
Time weighted rate of return
History of a dollar, needs to beginning and end balances, needs multipliers