The Term Structure of Interest Rates Chapter 3 Modeling Fixed-Income Securities and Interest Rate Option, 2nd Edition, Copyright © Robert A. Jarrow 2002 報告者 張富昇 陳郁婷 指導教授 戴天時 博士 Outline • • • • • • The economy The traded securities Interest rates Forward contracts Futures contracts Option contracts The Economy • Frictionless: -no transaction costs, no bid/ask spreads, no restrictions on trade, no taxes -If these traders determine prices, then this model approximates actual pricing and hedging well -frictionless markets v.s friction-filled markets The Economy • Competitive: -perfectly (infinitely) liquid -organized exchanges v.s over-the-counter markets • discrete trading:{0, 1, 2, ..., τ} -Continuous trading The Traded Securities • Money Market Account-shortest term zero-coupon bond 0 T T B(0)=$1 rdt 0 B(t ) e • Zero-coupon bond price t T P(t,T) $1 -default free , strictly positive prices Table 3.1: Hypothetical Zero-Coupon Bond Prices, Forward Rates and Yields PANEL A: FLAT TERMSTRUCTURE PANEL B: DOWNWARD SLOPING TERMSTRUCTURE PANEL C: UPWARD SLOPING TERMSTRUCTURE Time to Maturity (T) 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 Zero-Coupon Bond Forward Rates Prices P(O,T) f(O,T) 1 1.02 .980392 1.02 .961168 1.02 .942322 1.02 .923845 1.02 .905730 1.02 .887971 1.02 .870560 1.02 .853490 1.02 .836755 1 1.024431 .976151 1.023342 .953885 1.022701 .932711 1.022319 .912347 1.022025 .892686 1.021794 .873645 1.021627 .855150 1.021544 .837115 1.020748 .820099 1 1.016027 .984225 1.016939 .967831 1.017498 .951187 1.017836 .934518 1.018102 .917901 1.018312 .901395 1.018465 .885052 1.018542 .868939 1.019267 .852514 Yields y(O,T) 1.02 1.02 1.02 1.02 1.02 1.02 1.02 1.02 1.02 1.024431 1.023886 1.023491 1.023198 1.022963 1.022768 1.022605 1.022472 1.022281 1.016027 1.016483 1.016821 1.017075 1.017280 1.017452 1.017597 1.017715 1.017887 Panel A:flat term structure 1.024 Interest rates(%) 1.023 1.022 Forward Rates f(0,T) 1.021 Yields y(0,T) 1.02 1.019 0 1 2 3 4 5 6 7 Time to Maturity (T) 8 9 Panel B:downward-sloping term structure 1.025 Interest rates (%) 1.024 1.023 Forward Rates f(0,T) 1.022 Yields y(0,T) 1.021 1.02 0 1 2 3 4 5 6 Time to maturity (T) 7 8 9 Panel C:upward-sloping term structure 1.02 Interest rates (%) 1.019 1.018 Forward Rates f(0,T) 1.017 Yields y(0,T) 1.016 1.015 0 1 2 3 4 5 6 Time to maturity (T) 7 8 9 Term Structure of Interest Rates • The interest rates vary with maturity. • Concerned with how interest rates change with maturity. • The set of yields to maturity for bonds forms the term structure. -The bonds must be of equal quality. -They differ solely in their terms to maturity. Yield The yield (holding period return) at time t on a T-maturity zero-coupon bond is 1/(T t ) 1 y(t ,T ) P ( t , T ) <=> P(t ,T ) with y(t,T)>0 1 y(t ,T )(T t ) (3.1) (3.2) The yield is the internal rate of return on the zero-coupon bond. Forward rate The time t forward rate for the period [T,T+1] is f ( t ,T ) P ( t ,T ) P (t ,T 1) . --Implicit rate earned on the longer maturity bond over this last time period --One can contract at time t for a riskless loan over the time period [T,T+1] (3.3) TIME t T buy bond with maturity T P(t,T ) 1 sell P(t ,T ) P(t ,T 1) bonds with maturity T 1 TOTAL CASH FLOW P(t,T ) P(t,T 1) P(t,T 1) 0 T 1 P(t,T ) P(t,T 1) 1 P(t,T ) P(t,T 1) Table 3.2: A Portfolio Generating a Cash Flow Equal to Borrowing at the Time t Forward Rate for Date T, f(t,T). Forward rate f ( t ,T ) P ( t ,T ) P (t ,T 1) (3.3) Drive an expression for the bond’s price in terms of the various maturity forward rates: P ( t ,T ) 1 T 1 f (t , j ) j t (3.4) Derivation of Expression (3.4) step1. P (t , t ) 1 f (t , t ) ( P (t , t ) 1) P (t , t 1) P(t , t 1) 1 P (t , t 1) f (t , t ) step2. Next P (t , t 1) f (t , t 1) P (t , t 2) P (t , t 1) 1 P (t , t 2) f (t , t 1) f (t , t ) f (t , t 1) 1 P (t , t j ) f (t , t ) f (t , t 1) f (t , t 2) f (t , t j 1) Spot rate The spot rate is the rate contracted at time t on a one-period riskless loan starting immediately. P(t,t ) r (t ) f (t, t ) y(t,t 1) P(t,t 1) ( P(t , t ) 1, P(t , T ) 1 y(t , T ) T t P(t , t 1) 3.53.6 1 y(t , t 1) t 1t ) Return to the money market account: t 1 B(t ) B(t 1)r (t 1) r ( j ) j 0 (3.7) Interest rates Mark Name Meaning Zero-coupon bond price 到期日T的零息債券在時間t的價格 Money market account 時間t到T,以利率r(t)投資1元至到 期時的金額。在此表示,將1元投 入極短期zero-coupon bond y(t,T ) Yield Internal rate of return;時間t到T的 平均利率 f (t,T ) Forward rate 在時間點t下,將來時間點T的瞬間 利率 Spot rate;Zero rate 時間t的瞬時利率 P(t,T ) B(t ) r (t ) Forward Contracts • Forward contract – forward price a prespecified price that determined at the time the contract is written) – delivery or expiration date a prespecified date. – The contract has zero value at initiation. Forward Contracts • forward contracts on zero-coupon bonds: – the date the contract is written (t) – the date the zero-coupon bond is purchased or delivered (T1) – the maturity date of the zero-coupon bond (T2) – The dates must necessarily line up as t T1 T2 Forward Contracts – We denote the time t forward price of a contract with expiration date T1 on the T2-maturity zero-coupon bond as F(t,T1:T2) – F (T ,T :T ) P(T ,T ) 1 1 2 1 2 – The boundary condition or payoff to the forward contract on the delivery date is P(T ,T ) F (t,T :T ) 1 2 1 2 P(T1, T2) - F(t, T1: T2) 0 P(T1, T2) F(t, T1: T2) Figure 3.1: Payoff Diagram for a Forward Contract with Delivery Date T1 on a T2-maturity Zero-coupon Bond Futures Contracts • Futures contract – futures price A given price at the time the contract is written. The futures price is paid via a sequence of random and unequal installments over the contract's life. – delivery or expiration date a prespecified date. – The contract has zero value at initiation. Futures Contracts • futures contracts on zero-coupon bonds: – the date the contract is written (t) – the date the zero-coupon bond is purchased or delivered (T1) – the maturity date of the zero-coupon bond (T2) – The dates must necessarily line up as t T1 T2 Futures Contracts – We denote the time t futures price of a contract with expiration date T1 on the T2-maturity zero-coupon bond as F (t,T :T ) 1 2 – F (T ,T :T ) P(T ,T ) 1 1 2 1 2 – The cash flow to the futures contract at time t+1 is the change in the value of the futures contract over the preceding period [t,t+1], i.e F (t 1,T :T ) F (t,T :T ) 1 2 1 2 Futures Contracts – This payment occurs at the end of every period over the futures contract’s life. – This cash payment to the futures contract is called marking to the market. Time Forward Contract Futures Contract t 0 0 t+1 0 F t 1,T1: T2 – F t,T1: T2 t+2 0 F t 2,T1: T2 – F t 1,T1: T2 T1 1 0 F T1 1,T1: T2 – F T1 2,T1: T2 T1 PT1,T2 Ft,T1: T2 PT1,T2 F T1 1,T1: T2 SUM PT1,T2 F t,T1: T2 PT1,T2 F t,T1: T2 Table 3.3: Cash Flow Comparison of a Forward and Futures Contract • Let us decide whether a long position in a forward contract is preferred to a long position in a futures contract with delivery date on the same -maturity bond. If the forward contract is preferred, then the forward price should be greater than the futures price. i.e. F (t,T :T ) F (t ,T :T ) 1 2 1 2 F (t,T :T ) F (t ,T :T ) 1 2 1 2 • IF spot rate zero-coupon bond price the current futures price the change in the futures price is negative we need to borrow cash to cover the loss, and spot rates are high. F (t,T :T ) F (t ,T :T ) 1 2 1 2 • This is a negative compared to the forward contract that has no cash flow and an implicit borrowing rate set before rates increased. F (t,T :T ) F (t ,T :T ) 1 2 1 2 • IF spot rate zero-coupon bond price the current futures price the change in the futures price is positive after getting this cash profit, we need to invest it and spot rates are low. F (t,T :T ) F (t ,T :T ) 1 2 1 2 • This is a negative compared to the forward contract that has no cash flow and an implicit investment rate set before rates decreased. Option Contracts • A call option of the European a financial security that gives its owner the right to purchase a commodity at a prespecified price (strike price or exercise price) and at a predetermined date(maturity date or expiration date). • A call option of the American it allows the purchase decision to be made at any time from the date the contract is written until the maturity date. Option Contracts • A put option of the European a financial security that gives its owner the right to sell a commodity at a prespecified price (strike price or exercise price) and at a predetermined date(maturity date or expiration date). • A put option of the American it allows the sell decision to be made at any time from the date the contract is written until the maturity date. Option Contracts • a European call option with strike price K and maturity date T1 T2 written on this zerocoupon bond. Its time t price is denoted C (t ,T , K :T ) 1 2 • At maturity its payoff is: C(T1, T1, K: T2) = max [P(T1, T2) - K, 0] In-the-money Out-of-themoney K P(T1, T2) Figure 3.2: Payoff Diagram for a European Call Option on the T2-maturity Zero-coupon Bond with Strike K and Expiration Date T1 35 Option Contracts • a European put option with strike price K and maturity date T1 T2 written on this zerocoupon bond. Its time t price is denoted P (t,T , K :T ) 1 2 • At maturity its payoff is: P (T ,T , K :T ) max[ K P(T ,T ),0] 1 1 2 1 2 In-the-money Out-of-the-money K K P(T1, T2) Figure 3.3: Payoff Diagram for a European Put Option on the T2-maturity Zero-coupon Bond with Strike K and Expiration Date T1 37 Option Contracts • Put-call parity c KP(t , T1 ) p P(t , T2 ) • Protfolio A : European call + cash KP(t,T1 ) • Protfolio B: European put + bond (maturity at T2 ) P(T1 ,T2 )>K A B [P(T1 ,T2 )-K]+K 0+P(T1 ,T2 ) P(T1 ,T2 ) P(T1 ,T2 )<K 0+K [K-P(T1 ,T2 )]+P(T1 ,T2 ) K