CFA Level 1 — Derivatives
Intuition-First Study Guide · All 10 Readings
Derivative Instrument and Derivative Market Features
A derivative is simply a contract. Its value derives from some other asset (the "underlying"). Understanding derivatives starts with one insight: a derivative is a zero-sum game — every dollar gained by the long position is a dollar lost by the short position. The underlying asset doesn't change; the derivative just transfers risk between two parties.
What is a Derivative?
A derivative is a financial instrument whose value depends on the value of an underlying asset, rate, index, or other variable. The derivative itself is not the underlying — it is a contract about the underlying.
Underlying Assets
| Category | Examples | Key Derivatives Traded |
|---|---|---|
| Equities | Individual stocks, stock indices (S&P 500) | Equity futures, index options, equity swaps |
| Fixed Income | Government bonds, T-bills | Bond futures, interest rate swaps, FRAs |
| Currencies | EUR/USD, GBP/JPY | Currency forwards, FX futures, currency swaps |
| Commodities | Oil, gold, wheat, natural gas | Commodity futures, commodity swaps |
| Credit | Corporate bond spreads, loan pools | Credit default swaps (CDS), CDOs |
| Other Derivatives | Options on futures ("options on futures") | Swaptions, options on futures |
Exchange-Traded vs. OTC Derivatives Critical
Exchange-Traded (ETD)
- Standardised contracts (fixed size, expiry, terms)
- Trade on organised exchanges (CME, Eurex)
- Central counterparty clearing (CCP) eliminates bilateral default risk
- Margin requirements: initial + variation margin
- Daily mark-to-market (marking to market)
- High liquidity, transparent prices
- Cannot customise to exact needs
Over-the-Counter (OTC)
- Customised — any terms the two parties agree on
- Traded directly between dealers and end-users
- Bilateral counterparty credit risk (unless cleared)
- Less transparent — prices are negotiated
- Larger notional amounts typical
- Post-2008 reforms: more OTC now centrally cleared (ISDA/Dodd-Frank)
- ISDA Master Agreement governs most OTC derivatives
The Role of the Derivatives Dealer
Most OTC derivatives are initiated through a dealer (typically a large bank). The dealer acts as the market-maker: they take the opposite side of the client's trade, then hedge their own exposure elsewhere. The dealer earns a bid-ask spread, not by speculating on direction.
Forward Commitment and Contingent Claim Features and Instruments
Every derivative falls into one of two families. Forward commitments (forwards, futures, swaps) obligate both parties to perform — neither can walk away. Contingent claims (options) give the holder a right but not an obligation — the holder only exercises if it's advantageous. This distinction drives everything about how they are valued and used.
Forward Commitments
1. Forward Contracts
A privately negotiated (OTC) agreement to buy or sell an asset at a fixed price (forward price) on a specific future date. No money changes hands at initiation — the contract has zero cost to enter.
- Long forward: agrees to BUY at the forward price — profits if spot price rises above forward price at expiry
- Short forward: agrees to SELL at the forward price — profits if spot price falls below forward price at expiry
- Settled by delivery of the underlying (physical settlement) or cash payment of the difference (cash settlement)
2. Futures Contracts
An exchange-traded, standardised forward contract. Key feature: daily marking to market (variation margin). Both parties post initial margin and gains/losses are settled daily in cash — you can't accumulate large losses without the exchange noticing.
| Feature | Forward | Futures |
|---|---|---|
| Trading venue | OTC (bilateral) | Exchange-traded |
| Standardisation | Fully customisable | Standardised terms |
| Settlement | Single settlement at expiry | Daily mark-to-market |
| Counterparty risk | Yes — bilateral credit risk | Minimal — CCP guaranteed |
| Liquidity | Illiquid (hard to exit) | Highly liquid |
| Margin requirement | Typically none at initiation | Initial + variation margin |
| Price transparency | Private | Public market price |
3. Swaps
A series of forward contracts packaged together. The two parties exchange a series of cash flows over a specified period based on different references (e.g., fixed vs floating interest rates, or two different currencies).
- Interest Rate Swap (IRS): most common — exchange fixed payments for floating (SOFR-based) payments on a notional principal. Notional is NEVER exchanged — only the net difference in cash flows is paid.
- Currency Swap: exchange cash flows in different currencies, typically WITH exchange of principal at start and end.
- Equity Swap: exchange return on equity index for a fixed or floating rate.
- Credit Default Swap (CDS): protection buyer pays periodic premiums; protection seller pays the notional if the reference entity defaults.
Contingent Claims
4. Options
A contract giving the holder the right, but not the obligation, to buy (call) or sell (put) an underlying at a specified price (exercise/strike price) on or before a specified date. The buyer pays a premium upfront for this right.
| Type | Right Granted | Buyer Profits When... | Seller (Writer) Profits When... |
|---|---|---|---|
| Call Option | Right to BUY underlying at strike price | Underlying price rises above strike + premium | Underlying price stays below strike (option expires worthless — they keep premium) |
| Put Option | Right to SELL underlying at strike price | Underlying price falls below strike − premium | Underlying price stays above strike (option expires worthless — they keep premium) |
European vs. American Options
European Options
- Can ONLY be exercised at expiration
- Easier to value analytically (Black-Scholes)
- Most index options and many OTC options
American Options
- Can be exercised at ANY time before expiration
- More valuable than European (additional flexibility)
- Most exchange-traded stock options
5. Credit Derivatives Exam Focus
A Credit Default Swap (CDS) is the most important credit derivative. The protection buyer makes periodic premium payments (the "CDS spread") to the protection seller. If the reference entity defaults, the protection seller pays par value and receives the defaulted bonds.
Derivative Benefits, Risks and Issuer and Investor Uses
Why Derivatives Exist: The Economic Benefits
| Benefit | Explanation | Example |
|---|---|---|
| Risk Allocation / Transfer | Those who don't want risk can transfer it to those who do (or can bear it better) | Airline buys oil futures to lock in fuel costs; speculator takes the other side, bearing price risk in exchange for potential profit |
| Price Discovery | Futures markets aggregate information from many participants, producing forward-looking prices | Crude oil futures prices reflect market expectations of future supply/demand, visible to everyone |
| Operational Efficiency | Gaining exposure is faster and cheaper than transacting in the underlying | Buying S&P 500 futures is cheaper and faster than buying all 500 stocks |
| Leverage | Control large notional exposure with a small capital outlay (margin) | $5,000 margin controls $100,000 of futures contracts — 20:1 leverage |
| Short Selling Made Easy | Express bearish views without borrowing the underlying | Short equity futures to benefit from a market decline without stock-borrowing costs |
| Completing Markets | Enable payoff profiles that can't be replicated in spot markets | Volatility trades (e.g., buying straddles) are impossible without options |
Risks of Derivatives
1. Leverage Risk (Amplification)
Because a small margin deposit controls a large notional position, gains and losses are magnified relative to the capital invested. A 5% move in the underlying can wipe out 100% of your margin if the leverage is 20:1.
2. Counterparty Credit Risk
In OTC derivatives, if your counterparty defaults before the contract expires, you lose the mark-to-market gain you were owed. Exchange-traded derivatives eliminate this via CCP, but OTC exposure remains (partially mitigated by netting agreements and collateral under ISDA CSA).
3. Liquidity Risk
OTC derivatives can be very difficult to exit. Unlike exchange-traded contracts you can close with an offsetting trade, an OTC contract must be novated (assigned to a new counterparty) or terminated early, often at unfavourable prices.
4. Interconnectedness / Systemic Risk
Derivatives create webs of interdependence. If one major dealer defaults (like Lehman Brothers in 2008), the losses cascade through all counterparties. This is why post-2008 regulation pushed OTC derivatives toward central clearing.
Uses by Issuers (Corporations)
| Use Case | Derivative Used | Why |
|---|---|---|
| Hedge FX exposure on foreign revenues | FX forwards or options | Lock in exchange rate to remove earnings uncertainty |
| Fix interest costs on floating-rate debt | Pay-fixed interest rate swap | Convert variable-rate borrowing to predictable fixed payments |
| Lock in commodity input prices | Commodity futures or forwards | Stabilise margins by fixing cost of raw materials (e.g., fuel, metals) |
| Manage pension fund duration | Interest rate futures or swaps | Match liability duration without selling/buying actual bonds |
Uses by Investors
| Use Case | Derivative Used | Why |
|---|---|---|
| Hedge equity portfolio against market decline | Buy index put options or sell index futures | Downside protection without liquidating the portfolio |
| Enhance yield on existing holdings | Write (sell) covered call options | Collect premium; caps upside but generates income |
| Gain market exposure quickly | Buy equity futures or total return swap | Faster and cheaper than buying a basket of stocks |
| Express a view on volatility | Buy a straddle (call + put, same strike) | Profit if underlying moves sharply in either direction |
| Access otherwise hard-to-reach markets | Total return swaps, commodity swaps | Get commodity or EM equity exposure without holding actual assets |
Arbitrage, Replication and the Cost of Carry in Pricing Derivatives
Derivative pricing rests on one principle: no arbitrage. If a derivative is mispriced, traders will buy the cheap asset and sell the expensive one simultaneously, earning a riskless profit. This pressure immediately corrects the mispricing. The "correct" forward price is therefore exactly the price at which no arbitrage is possible — and this is derived from the cost of carry model.
The Law of One Price
If two portfolios produce identical future cash flows in all states of the world, they must have the same price today. If they don't, an arbitrage exists.
Replication
You can replicate the payoff of a forward contract with a portfolio of the underlying asset and a risk-free borrowing/lending position. Since the replicating portfolio has the same payoff as the forward, they must have the same price. This is how we derive the forward price.
Replication Portfolio for a Forward Contract
Consider a forward contract to buy stock S at price F in time T:
- Payoff at T: ST − F (long forward)
- Replication: Buy the stock today at S₀, borrow S₀ at the risk-free rate r. At T, you own the stock (worth ST) and owe S₀(1+r)^T. Net payoff: ST − S₀(1+r)^T
- For no arbitrage: F = S₀(1+r)^T
Forward price for a non-dividend-paying asset (discrete compounding)
Forward price (continuous compounding)
Cost of Carry — The General Framework Critical
The forward price equals the spot price plus the net cost of carry: all costs of holding the underlying asset minus all benefits received from holding it.
| Component | Effect on F₀ | Examples |
|---|---|---|
| Risk-free rate (r) | Increases F₀ | The financing cost of buying the underlying today instead of at T |
| Storage costs (c) | Increases F₀ | Warehouse fees for commodities (oil, gold, wheat) |
| Dividends (q) or coupon income | Decreases F₀ | Dividends on stock; coupon payments on bonds |
| Convenience yield (y) | Decreases F₀ | Benefit of having physical commodity on hand (e.g., oil in reserve for unexpected demand) |
Where c = PV of storage costs, i = PV of income/dividends received
Worked Example: Forward Price with Dividends
A stock trades at €50. The risk-free rate is 5% p.a. The stock pays a €2 dividend in 3 months. What is the 6-month forward price?
- PV of dividend = €2 / (1.05)^(0.25) = €1.976
- Adjusted spot = €50 − €1.976 = €48.024
- F₀ = €48.024 × (1.05)^0.5 = €48.024 × 1.0247 = €49.21
Arbitrage Mechanics: Cash-and-Carry and Reverse Cash-and-Carry
Cash-and-Carry (F₀ too HIGH)
- Actual F₀ > Fair F₀
- Action: Buy spot, borrow funds, sell (go short) the overpriced forward
- At expiry: deliver the asset, repay the loan
- Lock in a riskless profit = Actual F₀ − Fair F₀
Reverse Cash-and-Carry (F₀ too LOW)
- Actual F₀ < Fair F₀
- Action: Short sell the asset, invest proceeds, buy (go long) the underpriced forward
- At expiry: receive delivery, return borrowed asset
- Lock in a riskless profit = Fair F₀ − Actual F₀
Pricing and Valuation of Forward Contracts
Price vs. Value — this is the most important distinction in derivatives: The forward price (F₀) is fixed at initiation and never changes. The value of the forward contract changes continuously as the underlying spot price moves. At initiation, value = 0 by design. After initiation, value can be positive or negative.
Forward Price at Initiation
The forward price F₀ is set so that the initial value of the contract is zero — no money changes hands at initiation.
Value of a Forward Contract During Its Life Critical
After initiation, as the spot price changes and time passes, the forward contract acquires value. Let t be the current time (0 < t < T), St be the current spot price.
Simplified (no benefits or costs): the value of the long forward at time t is:
Worked Example: Valuing a Forward Mid-Life
6 months ago, you entered a 1-year forward to buy a non-dividend stock at F₀ = $104 (spot was $100, r = 4%). Now (at t = 6 months), the stock is at $112. What is the value of your long forward position?
- T − t = 0.5 years remaining
- PV of F₀ = $104 / (1.04)^0.5 = $104 / 1.0198 = $101.98
- Vt = St − PV(F₀) = $112 − $101.98 = $10.02
Forward Rate Agreements (FRAs) Exam Focus
An FRA is a forward contract on an interest rate. The buyer of an FRA locks in a borrowing rate; the seller locks in a lending rate. Settlement is at the beginning of the reference period (not the end).
An FRA(1×4) is a 3-month rate, starting in 1 month. Notation: FRA(m×n) means the rate starts in m months and ends in n months, so the underlying period is (n − m) months.
Forward Currency Pricing (Covered Interest Rate Parity)
The forward FX rate is determined by the interest rate differential between two countries. Higher interest rate currency trades at a forward discount.
Where rd = domestic interest rate, rf = foreign interest rate, quoted as domestic/foreign
Pricing and Valuation of Futures Contracts
Futures Price vs. Forward Price
In theory, if interest rates are deterministic (non-stochastic), futures prices equal forward prices for the same underlying, maturity, and terms. In practice, they can differ slightly due to the daily marking-to-market of futures.
When Futures Price > Forward Price
- When the underlying price is positively correlated with interest rates
- Gains on long futures position happen when rates are high (good reinvestment) → futures more valuable
- Example: T-bond futures — bond prices inversely correlate with rates, so actually futures < forwards for bonds
When Futures Price < Forward Price
- When the underlying price is negatively correlated with interest rates
- Example: Long-term bond futures — when rates fall, bond prices rise; margin gains happen when rates are low
Marking to Market and Margin
Initial Margin
A good-faith deposit required to enter a futures position. It is a fraction (typically 5–15%) of the contract's notional value. This is NOT a down payment — the full notional is still at risk.
Variation Margin (Daily Settlement)
Each day, gains and losses are credited or debited to your margin account. If your account falls below the maintenance margin, you receive a margin call and must deposit funds to restore the initial margin level.
Worked Example: Mark-to-Market
| Day | Futures Price | Daily P&L (Long) | Margin Balance |
|---|---|---|---|
| 0 (enter) | $1,000 | — | $5,000 (initial) |
| 1 | $1,010 | +$10 × 100 = +$1,000 | $6,000 |
| 2 | $985 | −$25 × 100 = −$2,500 | $3,500 |
| 2 (margin call) | — | Must deposit $1,500 | $5,000 (restored) |
| 3 | $990 | +$5 × 100 = +$500 | $5,500 |
Contango and Backwardation Exam Focus
Contango (Normal Market)
- Futures price > Spot price
- The normal case for financial assets (cost of carry is positive)
- Later expiry contracts priced higher
- Upward-sloping forward curve
Backwardation (Inverted Market)
- Futures price < Spot price
- Common for commodities with high convenience yield
- Occurs when immediate demand is very strong
- Downward-sloping forward curve
Basis and Basis Risk
Basis is not constant — it changes as time passes and as spot and futures prices move differently. Basis risk is the risk that the basis changes unexpectedly, causing a hedge to be imperfect.
Pricing and Valuation of Interest Rate and Other Swaps
An interest rate swap can be decomposed into a series of FRAs (forward rate agreements), one for each settlement date. Alternatively, it can be viewed as a fixed-rate bond vs. a floating-rate bond — the fixed-rate payer is short a fixed bond, long a floating bond. Both frameworks give the same answer for pricing and valuation.
Plain Vanilla Interest Rate Swap Structure
In a fixed-for-floating swap with notional N:
- Fixed-rate payer pays the swap rate (FS) × N × period fraction, receives SOFR × N × period fraction
- Floating-rate payer pays SOFR × N × period fraction, receives FS × N × period fraction
- Only the net payment is exchanged (netting reduces credit exposure)
- Notional principal is NEVER exchanged (unlike currency swaps)
Pricing the Swap: The Swap Rate Critical
The swap rate (fixed rate) is set so that the swap's initial value is zero. This means the present value of all fixed payments must equal the present value of all expected floating payments.
Where Zi = discount factor for period i (PV of $1 received at time i)
Or equivalently:
PV(fixed payments) + PV(final notional exchange) = par (=1 on a per-unit basis)
Worked Example: Pricing a 2-Year Annual Pay Swap
Given spot rates: S₁ = 4%, S₂ = 5%. Calculate the swap rate.
- Z₁ = 1/(1.04)¹ = 0.9615
- Z₂ = 1/(1.05)² = 0.9070
- FS = (1 − Z₂) / (Z₁ + Z₂) = (1 − 0.9070) / (0.9615 + 0.9070) = 0.0930 / 1.8685 = 4.978% ≈ 4.98%
Valuing a Swap During Its Life Exam Focus
After initiation, interest rates change, and the swap acquires value. From the fixed-rate payer's perspective, the swap is like being long a floating-rate bond (worth par, since it resets) and short a fixed-rate bond.
If rates have risen since the swap was initiated, the fixed-rate payer benefits (they locked in the old, lower fixed rate, and the market now demands more). The swap is worth positive to the fixed-rate payer.
Currency Swaps
Unlike interest rate swaps, currency swaps involve the exchange of principal in two different currencies at the start and end of the swap. During the swap, interest payments in both currencies are exchanged.
| Feature | Interest Rate Swap | Currency Swap |
|---|---|---|
| Principal exchange | No (never exchanged) | Yes — at inception AND maturity |
| Currency of cash flows | Single currency (net settlement) | Two different currencies |
| FX risk | None | Significant — payments are in different currencies |
| Credit exposure | Only interest differential | Principal + interest (larger notional at risk) |
Pricing and Valuation of Options
Unlike forward contracts (which have a zero initial value by design), options have a positive premium because they give one-sided rights. The option price has two components: intrinsic value (what it's worth if exercised right now) and time value (the extra premium for the possibility of future favourable moves). Time value always erodes to zero at expiry.
Option Value Components
| Component | Call | Put |
|---|---|---|
| Intrinsic Value | max(0, S − X) → profit if exercised NOW | max(0, X − S) → profit if exercised NOW |
| Time Value | Option Price − Intrinsic Value | Option Price − Intrinsic Value |
| At Expiry | Time Value = 0; Price = max(0, ST − X) | Time Value = 0; Price = max(0, X − ST) |
Moneyness Exam Focus
| Status | Call (right to buy) | Put (right to sell) | Intrinsic Value |
|---|---|---|---|
| In-the-money (ITM) | S > X | S < X | Positive |
| At-the-money (ATM) | S = X | S = X | Zero |
| Out-of-the-money (OTM) | S < X | S > X | Zero (but time value still positive) |
The Six Factors Affecting Option Prices Critical
| Factor | ↑ Factor Effect on Call | ↑ Factor Effect on Put | Why |
|---|---|---|---|
| Underlying Price (S) | ↑ Call Value | ↓ Put Value | Higher S → call more ITM, put more OTM |
| Strike Price (X) | ↓ Call Value | ↑ Put Value | Higher X → call harder to reach, put easier to reach |
| Time to Expiry (T) | ↑ Call Value (usually) | ↑ Put Value (usually) | More time = more chance of favourable move (American always; European generally) |
| Volatility (σ) | ↑ Call Value | ↑ Put Value | Higher vol = bigger possible moves both up and down; option holder benefits from big moves, not harmed by bad moves (floor at zero) |
| Risk-Free Rate (r) | ↑ Call Value | ↓ Put Value | Higher r → PV of strike lower → call more valuable; higher r → PV of put payoff lower |
| Dividends/Distributions (D) | ↓ Call Value | ↑ Put Value | Dividend reduces stock price on ex-date → call less valuable, put more valuable |
Boundary Conditions for European Options
Lower Bounds
The call's lower bound is the current spot minus the PV of the strike. The put's lower bound is the PV of the strike minus the spot. Options can never have negative value (no one exercises an option at a loss).
Upper Bounds
Early Exercise of American Options
American Call on Non-Dividend Stock
- Early exercise is NEVER optimal
- Exercising destroys time value — better to sell the option
- Therefore: American call = European call (same price)
American Put on Any Stock
- Early exercise CAN be optimal for deep ITM puts
- If S → 0, waiting adds little but you forego the time value of strike X
- American put > European put always
Option Replication Using Put-Call Parity
Put-call parity is the cornerstone of option pricing theory. It establishes a precise no-arbitrage relationship between call prices, put prices, the underlying stock, and a risk-free bond. If this relationship is violated, you can earn a riskless profit by buying the underpriced combination and selling the overpriced one. More importantly, it means you can replicate any one instrument using the other three.
Put-Call Parity: The Formula Critical
For European options on non-dividend-paying stocks
Verbally: Call + PV(Strike) = Put + Stock. Both sides create the same payoff profile at expiry.
Proof: Why Both Sides Have the Same Payoff at Expiry
| Scenario | Portfolio A: Call + PV(X) invested at r | Portfolio B: Put + Stock |
|---|---|---|
| ST > X (call ITM) | Call pays ST − X; bond pays X → total = ST | Put expires worthless (0); stock worth ST → total = ST |
| ST < X (put ITM) | Call expires worthless (0); bond pays X → total = X | Put pays X − ST; stock worth ST → total = X |
Synthetic Positions from Put-Call Parity Exam Focus
You can rearrange put-call parity to solve for any one instrument in terms of the others:
| Synthetic Position | Components | Formula |
|---|---|---|
| Synthetic Long Call | Long put + Long stock + Borrow PV(X) | c = p + S₀ − PV(X) |
| Synthetic Long Put | Long call + Short stock + Lend PV(X) | p = c − S₀ + PV(X) |
| Synthetic Long Stock | Long call + Short put + Lend PV(X) | S₀ = c − p + PV(X) |
| Synthetic Risk-Free Bond | Long stock + Long put + Short call | PV(X) = p + S₀ − c |
| Synthetic Long Forward | Long call + Short put (same strike) | F₀ equivalent payoff = c − p |
Put-Call Parity for Options on Forwards/Futures
For European options on a forward or futures contract (where the underlying is a forward price F₀):
Or equivalently: c − p = PV(F₀ − X). The difference between a call and a put price equals the PV of the difference between the forward price and the strike price.
Arbitrage Using Put-Call Parity
Example: Detecting Mispricing
S = $100, X = $100, T = 1 year, r = 5%. Call trades at $10.00. What must the put trade at?
- PV(X) = $100/1.05 = $95.24
- Put = c − S₀ + PV(X) = $10.00 − $100 + $95.24 = $5.24
- If put actually trades at $7.00 (too expensive):
- Arbitrage: Sell the put, sell the stock short, buy the call, invest PV(X) = $95.24
- Riskless profit = $7.00 − $5.24 = $1.76 per share (at initiation)
Valuing a Derivative Using a One-Period Binomial Model
The binomial model is the conceptual foundation of all options pricing. Its core insight is profound: you don't need to know what probability the stock will go up to price an option. Instead, you construct a replicating portfolio that exactly mimics the option's payoff. Since the portfolio and the option produce identical cash flows, they must have the same price — regardless of actual probabilities.
The One-Period Binomial Framework
The stock can move in only two ways over the next period:
- Up: S moves to S+ = S × u (where u > 1)
- Down: S moves to S− = S × d (where 0 < d < 1)
Risk-Neutral Probability Critical
We use a risk-neutral probability π (not the real-world probability) such that the expected return on the stock equals the risk-free rate. This is the key trick — by repricing probabilities to make all assets earn the risk-free rate, we can discount option payoffs at the risk-free rate.
Option Price: The Binomial Formula Critical
Where c⁺, c⁻ are the option payoffs in the up and down states respectively
Worked Example: Pricing a Call Option
Stock: S = $100, u = 1.10, d = 0.90, rf = 5%, X = $100 (ATM call).
Step 1: Calculate up and down stock prices.
- S+ = $100 × 1.10 = $110
- S− = $100 × 0.90 = $90
Step 2: Calculate option payoffs at expiry.
- c+ = max(0, $110 − $100) = $10
- c− = max(0, $90 − $100) = $0
Step 3: Calculate risk-neutral probability.
- π = (1.05 − 0.90) / (1.10 − 0.90) = 0.15 / 0.20 = 0.75
- 1 − π = 0.25
Step 4: Calculate option price.
The Replicating Portfolio Approach (Alternative Method)
Construct a portfolio of Δ shares of stock and a bond B that exactly replicates the option payoffs:
This Δ is the hedge ratio (option delta) — the number of shares needed to hedge one option.
Continuing the Example:
- Δ = ($10 − $0) / ($110 − $90) = $10 / $20 = 0.50
- Portfolio: Long 0.50 shares, short 1 call. This portfolio is riskless.
- Up state: 0.50 × $110 − $10 = $55 − $10 = $45
- Down state: 0.50 × $90 − $0 = $45 − $0 = $45 ✓ (same in both states)
- PV of $45 = $45 / 1.05 = $42.86
- Value of hedge portfolio today: 0.50 × $100 − c = $42.86 → c = $50 − $42.86 = $7.14 ✓
No-Arbitrage Constraint on u and d
For no-arbitrage to hold, we need:
If the risk-free rate is outside the range [d, u], an arbitrage exists — you could earn more than the risk-free rate with zero risk by combining the stock and the riskless asset.
Step 2: Risk-neutral prob. π = (1.06 − 0.80)/(1.20 − 0.80) = 0.26/0.40 = 0.65; 1−π = 0.35.
Step 3: Put price. p = (0.65 × $0 + 0.35 × $10)/1.06 = $3.50/1.06 = $3.30.
Verify with delta: Δ = ($0 − $10)/($60 − $40) = −0.50 (short 0.50 shares to replicate the put).
Master Formula Sheet — All 10 Derivative Readings
| Formula | Description | Reading |
|---|---|---|
| \(F_0 = S_0 \cdot (1+r_f)^T\) | Forward price — no income/costs | 69/70 |
| \(F_0 = (S_0 - PV(\text{benefits}) + PV(\text{costs})) \cdot (1+r_f)^T\) | Forward price — with carry costs/benefits | 69/70 |
| \(F_0 = S_0 \cdot e^{r_f T}\) | Forward price — continuous compounding | 69/70 |
| \(V_t = S_t - F_0 / (1+r_f)^{T-t}\) | Long forward value mid-life | 70 |
| \(V_T = S_T - F_0\) | Forward payoff at expiry (long) | 70 |
| \(F_0 = S_0 \cdot (1+r_d)^T / (1+r_f)^T\) | Forward FX rate (covered interest parity) | 70 |
| \(\text{Basis} = S - F\) | Futures basis (converges to 0 at expiry) | 71 |
| \(FS = \frac{1-Z_N}{\sum Z_i}\) | Swap rate (fixed rate at initiation) | 72 |
| \(V_{\text{fixed payer}} = V_{\text{float}} - V_{\text{fixed bond}}\) | Swap value during life | 72 |
| \(c = \max(0, S - X)\) | Call option intrinsic value | 73 |
| \(p = \max(0, X - S)\) | Put option intrinsic value | 73 |
| \(c \geq \max(0, S_0 - X/(1+r)^T)\) | Call lower bound (European) | 73 |
| \(p \geq \max(0, X/(1+r)^T - S_0)\) | Put lower bound (European) | 73 |
| \(c + X/(1+r)^T = p + S_0\) | Put-call parity (European, no dividends) | 74 |
| \(\pi = \frac{(1+r_f) - d}{u - d}\) | Risk-neutral probability (up) | 75 |
| \(c = \frac{\pi \cdot c^+ + (1-\pi) \cdot c^-}{1+r_f}\) | Call price — binomial model | 75 |
| \(\Delta = \frac{c^+ - c^-}{S^+ - S^-}\) | Hedge ratio / option delta (binomial) | 75 |
| \(\text{FRA settlement} = \frac{(\text{FR}-\text{FRA rate}) \cdot \text{Days}/360}{1+\text{FR} \cdot \text{Days}/360} \cdot N\) | FRA cash settlement payment | 70 |
Common Exam Traps — Derivatives Critical
| Trap | The Mistake | The Correct Thinking |
|---|---|---|
| Swap notional exchange | Assuming notional is exchanged in an interest rate swap | Notional is NEVER exchanged in IRS; it IS exchanged at start and end in currency swaps |
| Zero initial value | Saying forwards/futures cost something to enter | Forwards/futures have zero value at initiation (no money changes hands); options require a premium |
| Put-call parity scope | Applying c + PV(X) = p + S₀ to American options | Put-call parity holds exactly only for European options; gives bounds for American options |
| Volatility and puts | Saying higher volatility hurts puts | Higher volatility ALWAYS increases both call and put values |
| Risk-neutral probability | Using actual (real-world) probability in binomial model | The binomial model uses risk-neutral probabilities derived from u, d, r — not actual probabilities |
| Early call exercise | Saying American call = European call always | Only true for non-dividend-paying stocks. With dividends, early exercise can be optimal just before ex-date |
| Futures vs. forward pricing | Always assuming futures price ≠ forward price | Treat as equal for exam purposes unless specifically told there is a correlation effect |
| FRA settlement timing | Collecting FRA settlement at the end of the reference period | FRA settles at the BEGINNING of the reference period (discounted PV of the payment) |
| Basis direction | Confusing basis as always positive | Basis = Spot − Futures. In contango (futures > spot), basis is negative. Basis converges to 0. |
| Fixed-rate payer in IRS | Thinking the fixed payer gains when rates fall | Fixed payer gains when rates RISE (they locked in a low rate; market now demands more) |