Option Strategies & Exotics 1 Note on Notation • Here, T denotes time to expiry as well as time of expiry, i.e. we use T to denote indifferently T and δ = T – t • Less accurate but handier this way, I think 2 Types of Strategies • Take a position in the option and the underlying • Take a position in 2 or more options of the same type (A spread) • Combination: Take a position in a mixture of calls & puts (A combination) 3 Positions in an Option & the Underlying Profit Profit K K ST ST (a) (b) Profit Profit K ST (c) K ST (d) Basis of Put-Call Parity: P + S = C + Cash ( Ke-rT) 4 Bull Spread Using Calls Profit ST K1 K2 5 Bull Spread Using Calls Example • Create a bull spread on IBM using the following 3month call options on IBM: Option 1: Strike: K1 = 102 Price: C1 = 5 Option 2: Strike: K1 = 110 Price: C2 = 2 Gamble on stock price rise and offset cost with sale of call +1 Long Call (at K1) +1 0 K1 0 plus K2 Short Call (at K2 > K1) -1 0 Profit equals 0 5 Call Bull Spread +1 K1=102 K2=110 0 -3 SBE=105 Share Price Payoff: Long call (K1) + short call (K2) = Bull Spread: { 0, +1, +1} + {0, 0, -1} = {0, +1, 0 } = Max(0, ST-K1) – C1 – Max(0, ST-K2) + C2 = C2 - C1 if ST K1 K2 = ST - K1 + (C2 - C1) if K1 < ST K2 = (ST - K1 - C1) + (K2 - ST + C2) = = K2 - K1 + (C2 - C1) if ST > K1 > K2 ‘Break-even’: SBE = K1 + (C1 – C2) = 102 + 3 = 105 Bear Spread Using Puts Profit K1 K2 ST 9 Bull Spreads with puts & Bear Spreads with Calls • Of course can do bull spreads with puts and bear spreads with calls (put-call parity) • Figured out how? 10 Bull Spread Using Puts Profit K1 K2 ST 11 Bear Spread Using Calls Profit K1 K2 ST 12 Equity Collar You already hold stocks but you want to limit downside (buy a put) but you are also willing to limit the upside if you can earn some cash today (by selling an option, i.e. a call) COLLAR = long stock + long put (K1) + short call (K2) {0,+1,0} = {+1,+1,+1} + {-1,0,0} + {0,0,-1} Equity Collar: Payoff Profile +1 +1 Long Stock +1 plus -1 0 0 Long Put plus 0 0 -1 Short Call equals 0 0 +1 Equity Collar Equity Collar Payoffs ST < K 1 K1 ST K2 ST > K 2 Long Shares ST ST ST Long Put (K1) K1 – ST 0 0 Short Call (K2) 0 0 – (ST – Gross Payoff K1 ST K2 Net Profit K1 – (P – C) ST – (P – C) K2 – (P – C) Net Profit = Gross Payoff – (P – C) K2) Box Spread • A combination of a bull call spread and a bear put spread • If all options are European a box spread is worth the present value of the difference between the strike prices • Check it out • If they are American this is not necessarily so 16 A Basic Combination: A Synthetic Forward/Futures 0 +1 Short Put plus 0 +1 Long Call equals +1 +1 Long Futures Range Forward Contracts • Have the effect of ensuring that the exchange rate paid or received will lie within a certain range • When currency is to be paid it involves selling a put with strike K1 and buying a call with strike K2 (with K2 > K1) • When currency is to be received it involves buying a put with strike K1 and selling a call with strike K2 • Normally the price of the put equals the price of the call 18 Range Forward Contract Payoff Payoff Asset Price K1 Short Position K2 K1 K2 Asset Price Long Position 19 Volatility Combinations • Mainly • Straddle • Strangles • These are strategies that show the true ‘character’ of options • But also • Strip • Straps • Etc. A Straddle Combination Profit K ST 21 Long (buy) Straddle Data: K = 102 P=3 C=5 C+P=8 profit long straddle: = Max (0, ST – K) - C + Max (0, K – ST) – P = 0 for ST > K => ST - K – (C + P) = K + (C + P) = 102 + 8 = 110 for ST < K => K - ST – (C + P) = K - (C + P) = 102 - 8 = 94 Straddles and HF • Fung and Hsieh (RFS, 2001) empirically show that many hedge funds follow strategies that resemble straddles: • ‘Market timers’ returns are highly correlated with the return to long straddles on diversified equity indices and other basic asset classes A Strangle Combination Profit K1 K2 ST 24 Strip & Strap Profit Profit K Strip ST K ST Strap 25 Time Decay Combinations • Calendar (or horizontal) spreads • Options, same strike price (K) but different maturity dates, e.g. buying a long dated option (360-day) and selling a short dated option (180-day), both are at-the money • In a relatively static market (i.e. S0 = K) this spread will make money from time decay, but will loose money if the stock price moves substantially Calendar Spread Using Calls Profit ST K 27 Calendar Spread Using Puts Profit ST K 28 ‘Quasi-Elementary’ Securities • Arrow(-Debrew) introduces so called ArrowDebrew elementary securities, i.e. contingent claims with $1 payoff in one state and $0 in all other states • These can be seen as “bet” options • Butterflies look a lot like them Butterfly Spread Using Calls Profit K1 K2 K3 ST 30 Butterfly Spread Using Puts Profit K1 K2 K3 ST 31 Butterflies Replication • Butterfly requires: • sale of 2 ‘inner-strike price’ call options (K2) • purchase of 2 'outer-strike price’ call options (K1, K3) • Butterfly is a ‘bet’ on a small change in price of the underlying in either direction • Potential downside of the ‘bet’ is offset by ‘truncating’ the payoff by buying some options • Could also buy (go long) a bull and a bear (call or put) spread, same result Short Butterflies Replication • Short butterfly requires: • purchase of 2 ‘inner-strike price’ call options (K2) • sale of 2 'outer-strike price’ call options (K1, K3) • Short butterfly is a ‘bet’ on a large change in price of the underlying in either direction (e.g. result of reference to the competition authorities) • Cost of the ‘bet’ is offset by ‘truncating’ the payoff by selling some options • Could also sell (go short) a bull and a bear (call or put) spread, same result Short Butterfly Spread Using Calls Profit K1 K2 K3 ST 34 Variations Using Interest Rate Options 35 Interest Rate Options • Interest rate option gives holder the right but not the obligation to receive one interest rate (e.g. floating\LIBOR) and pay another (e.g. the fixed strike rate LK) Caps • A cap is a portfolio of “caplets” • Each caplet is a call option on a future LIBOR rate with the payoff occurring in arrears • Payoff at time tk+1 on each caplet is Ndk max(Lk - LK, 0) where N is the notional amount, dk = tk+1 - tk , LK is the cap rate, and Lk is the rate at time tk for the period between tk and tk+1 • It has the effect of guaranteeing that the interest rate in each of a number of future periods will not rise above a certain level Caplet Payoff Strike rate LK fixed in the contract t0 = 0 Expiry \ Valuation of option, (LIBOR1 - LK) t1 = 30 t2 = 120 days δ = 90 days 38 Annualised Cost of Borrowing Planned Borrowing + Caplet (Call on Bond) 18 16 14 12 10 8 6 4 5 7 9 11 LIBOR at expiry 13 15 Annualized return on loan Loan + Interest Rate Floorlet (Put on Bond) 20 15 10 5 0 4 6 8 10 12 LIBOR at expiry 14 16 Positions in an Option & the Underlying (notice variables on vertical axis) Long floorlet Return rate Return rate Short caplet K K iT iT (b) (a) Long caplet Short floorlet Funding cost Funding cost K K (c) iT iT (d) 41 Collar Comprises a long cap and short floor. It establishes both a floor and a ceiling on a corporate or bank’s (floating rate) borrowing costs. Effective Borrowing Cost with Collar (at T tk+1 = tk + 90) = = [Lk – max[{0, Lk – LK} + max {0, LK – Lk}]N(90/360) = Lk,CAP N(90/360) if Lk > Lk,CAP = Lk,FL N(90/360) if Lk < Lk,FL = Lk (90/360) if Lk,FL < Lk < Lk,CAP Collar involves borrowing cost at each payment date of either Lk,CAP = 10% or Lk,FL = 8% or Lk = LIBOR if the latter is between 8% and 10%. 42 Combining options with swaps • Cancelable swaps - can be cancelled by the firm entering into the swap if interest rates move a certain way • Swaptions - options to enter into a swap Swaptions • OTC option for the buyer to enter into a swap at a future date and a predetermined swap rate A payer swaption gives the buyer the right to enter into a swap where they pay the fixed leg and receive the floating leg (long IRS). A receiver swaption gives the buyer the right to enter into a swap where they will receive the fixed leg, and pay the floating leg (short IRS). Swaptions Example • A US bank has made a commitment to lend at fixed rate $10m over 3 years beginning in 2 years time and may need to fund this loan at a floating rate. • In 2 years time, the bank may wish to swap the floating rate payments for a fixed rate, • Perhaps at that time, the bank may think that interest rates may rise over the 3 years and hence the cost of the fixed rate payments in the swap will be higher than at inception. Example • Bank might need a $10m swap, to pay fixed and receive floating beginning in 2 years time and an agreement that swap will last for further 3 years • The bank can hedge by purchasing a 2-year European payer swaption, with expiry in T = 2, on a 3 year “pay fixed-receive floating” swap, at say sK = 10%. • Payoff is the annuity value of Nδmax{sT – sK, 0}. So, value of swaption at T is: • f = $10m[sT – sK] [(1 + L2,3)-1 + (1 + L2,4)-2 + (1 + L2,5)-3] Exotics 47 Types of Exotics • Package • Nonstandard American options • Forward start options • Compound options • Chooser options • Barrier options • Binary options • Lookback options • Shout options • Asian options • Options to exchange one asset for another • Options involving several assets • Volatility and Variance swaps • etc., etc., etc. 48 Packages • Portfolios of standard options • Classical spreads and combinations: bull spreads, bear spreads, straddles, etc • Often structured to have zero cost • One popular package is a range forward contract 49 Non-Standard American Options • Exercisable only on specific dates (Bermudans) • Early exercise allowed during only part of life (initial “lock out” period) • Strike price changes over the life (warrants, convertibles) 50 Forward Start Options • Option starts at a future time, T1 • Implicit in employee stock option plans • Often structured so that strike price equals asset price at time T1 51 Compound Option • Option to buy or sell an option Call on call Put on call Call on put Put on put • Can be valued analytically • Price is quite low compared with a regular option 52 Chooser Option “As You Like It” • Option starts at time 0, matures at T2 • At T1 (0 < T1 < T2) buyer chooses whether it is a put or call • This is a package! 53 Chooser Option as a Package At time T1 the value is max(c, p) From put - call parity p c e r (T2 T1 ) K S1e q (T2 T1 ) The value at time T1 is therefore max(c, p) c e q (T2 T1 ) max(0, Ke ( r q )( T2 T1 ) S1 ) max 0,e r ( T2 T1 ) K S1e q ( T2 T1 ) This is a call maturing at time T2 plus a put maturing at time T1 with strike Ke ( r q )( T2 T1 ) 54 Barrier Options • Option comes into existence only if stock price hits barrier before option maturity ‘In’ options • Option dies if stock price hits barrier before option maturity ‘Out’ options 55 Barrier Options (continued) • Stock price must hit barrier from below ‘Up’ options • Stock price must hit barrier from above ‘Down’ options • Option may be a put or a call • Eight possible combinations 56 Parity Relations c = cui + cuo c = cdi + cdo p = pui + puo p = pdi + pdo 57 Binary Options • Cash-or-nothing: pays Q if ST > K, otherwise pays nothing. Value according to B&S = e–rT Q N(d2) • Asset-or-nothing: pays ST if ST > K, otherwise pays nothing. Value according to B&S = S0e-qT N(d1) 58 Decomposition of a Call Option Long Asset-or-Nothing option Short Cash-or-Nothing option where payoff is K Value according to B&S = S0e-qT N(d1) – e–rT KN(d2) 59 Asian Options • Payoff related to average stock price • Average Price options pay: Call: max(Save – K, 0) Put: max(K – Save , 0) • Average Strike options pay: Call: max(ST – Save , 0) Put: max(Save – ST , 0) 60 Asian Options • No exact analytic valuation • Can be approximately valued by assuming that the average stock price is lognormally distributed 61 Lookback Options • Floating lookback call pays ST – Smin at time T (Allows buyer to buy stock at lowest observed price in some interval of time) • Floating lookback put pays Smax– ST at time T (Allows buyer to sell stock at highest observed price in some interval of time) • Fixed lookback call pays max(Smax−K, 0) • Fixed lookback put pays max(K −Smin, 0) • Analytic valuation for all types 62 Shout Options • Buyer can ‘shout’ once during option life • Final payoff is either Usual option payoff, max(ST – K, 0), or Intrinsic value at time of shout, St – K • Payoff: max(ST – St , 0) + St – K • Similar to lookback option but cheaper 63 Exchange Options • Option to exchange one asset for another • For example, an option to exchange one unit of U for one unit of V • Payoff is max(VT – UT, 0) 64 Basket Options • A basket option is an option to buy or sell a portfolio of assets • This can be valued by calculating the first two moments of the value of the basket and then assuming it is lognormal 65 Volatility and Variance Swaps • Agreement to exchange the realized volatility between time 0 and time T for a pre-specified fixed volatility with both being multiplied by a pre-specified principal • Variance swap is agreement to exchange the realized variance rate between time 0 and time T for a pre-specified fixed variance rate with both being multiplied by a prespecified principal • Daily expected return is assumed to be zero in calculating the volatility or variance rate 66 Variance Swaps • The (risk-neutral) expected variance rate between times 0 and T can be calculated from the prices of European call and put options with different strikes and maturity T • Variance swaps can therefore be valued analytically if enough options trade • For a volatility swap it is necessary to use the approximate relation 1 var(V ) ˆ ˆ E ( ) E V 1 2 ˆ 8 E (V ) 67 VIX Index • The expected value of the variance of the S&P 500 over 30 days is calculated from the CBOE market prices of European put and call options on the S&P 500 • This is then multiplied by 365/30 and the VIX index is set equal to the square root of the result 68 How Difficult is it to Hedge Exotic Options? • In some cases exotic options are easier to hedge than the corresponding vanilla options (e.g., Asian options) • In other cases they are more difficult to hedge (e.g., barrier options) 69 Static Options Replication (Hard Topic) • This involves approximately replicating an exotic option with a portfolio of vanilla options • Underlying principle: if we match the value of an exotic option on some boundary , we have matched it at all interior points of the boundary • Static options replication can be contrasted with dynamic options replication where we have to trade continuously to match the option 70 Example • A 9-month up-and-out call option an a non-dividend paying stock where S0 = 50, K = 50, the barrier is 60, r = 10%, and = 30% • Any boundary can be chosen but the natural one is c (S, 0.75) = MAX(S – 50, 0) when S < 60 c (60, t ) = 0 when 0 t 0.75 71 Example (continued) We might try to match the following points on the boundary c(S , 0.75) = MAX(S – 50, 0) for S < 60 c(60, 0.50) = 0 c(60, 0.25) = 0 c(60, 0.00) = 0 72 Example continued We can do this as follows: +1.00 call with maturity 0.75 & strike 50 –2.66 call with maturity 0.75 & strike 60 +0.97 call with maturity 0.50 & strike 60 +0.28 call with maturity 0.25 & strike 60 73 Example (continued) • This portfolio is worth 0.73 at time zero compared with 0.31 for the up-and out option • As we use more options the value of the replicating portfolio converges to the value of the exotic option • For example, with 18 points matched on the horizontal boundary the value of the replicating portfolio reduces to 0.38; with 100 points being matched it reduces to 0.32 74 Using Static Options Replication • To hedge an exotic option we short the portfolio that replicates the boundary conditions • The portfolio must be unwound when any part of the boundary is reached 75 Exercises • 8.1 • 10.1 76