Core concepts
- 01Forward: customised OTC; Futures: exchange-traded standardised.
- 02Options: Call (right to buy), Put (right to sell); American (anytime) vs European (expiry).
- 03Option payoff at expiry: Call = max(S−K, 0), Put = max(K−S, 0).
- 04Black-Scholes model for European options on non-dividend-paying stock.
- 05Greeks: Delta (price sensitivity), Gamma, Theta, Vega, Rho.
Flowchart summary
Option Valuation | Intrinsic Value + Time Value = Premium | ITM / ATM / OTM | Models: Binomial / Black-Scholes | Greeks measure sensitivities
Exam-critical pointers
- ⭐Put-Call parity violation → arbitrage opportunity.
- ⭐Currency forward: Interest Rate Parity F = S × (1 + ih) / (1 + if).
- ⭐Swap: equivalent to series of forward contracts.
- ⭐Binomial model useful for American options & path-dependent options.
Elaborative notes
Derivatives Analysis & Valuation
Derivatives are contracts whose value is derived from an underlying — a
stock, index, interest rate, currency, or commodity. AFM tests four
instruments (forwards, futures, options, swaps) and three valuation lenses
(no-arbitrage forward pricing, put-call parity, binomial / Black-Scholes for
options).
1. The four basic instruments
| Instrument | Customised? | Counterparty | Cash flow |
|---|---|---|---|
| Forward | Yes (OTC) | Specific bank / dealer | Net at maturity |
| Futures | No (exchange-standardised) | Clearing corporation | Daily MTM + margin |
| Option | OTC or exchange | Writer (counterparty) | Premium upfront + payoff at expiry |
| Swap | OTC | Counterparty | Periodic exchange of cash flows |
2. Forward / futures pricing — the no-arbitrage rule
For a non-dividend-paying asset:
F = S × e^(r × T) (continuous compounding)
F = S × (1 + r × T) (simple)
If the actual forward deviates from this, an arbitrage opportunity exists —
borrow / lend the difference and lock in a riskless profit.
For an asset paying a known dividend yield q:
F = S × e^((r − q) × T)
For a currency (Interest Rate Parity, repeated from forex chapter):
F = S × (1 + r_dom × t) / (1 + r_for × t)
3. Options — payoff and pricing
3.1 Payoff at expiry
| Position | Payoff |
|---|---|
| Long call | max(S − K, 0) − premium paid |
| Long put | max(K − S, 0) − premium paid |
| Short call | premium received − max(S − K, 0) |
| Short put | premium received − max(K − S, 0) |
S = spot at expiry, K = strike.
3.2 Intrinsic value vs time value
Option premium = Intrinsic value + Time value
Intrinsic value:
- •Call: max(S − K, 0)
- •Put: max(K − S, 0)
Time value is the remaining premium — pure optionality. Decays to zero at
expiry (Theta).
3.3 Moneyness
| Call | Put | |
|---|---|---|
| ITM (in the money) | S > K | S < K |
| ATM (at the money) | S = K | S = K |
| OTM (out of the money) | S < K | S > K |
3.4 Put-Call parity (European options, non-dividend)
C − P = S − K × e^(−r × T)
This relationship must hold at all times — any deviation creates an
arbitrage. ICAI loves to test this: give 3 of (C, P, S, K, r) and ask the 4th.
3.5 The two pricing models you must know
Binomial model:
- Up factor u, down factor d, risk-free rate r per period.
- Risk-neutral probability p = (e^(r×t) − d) / (u − d).
- Option value at each node = expected payoff under p discounted by r.
Best for American options and path-dependent payoffs.
Black-Scholes (European, non-dividend, log-normal):
Call = S × N(d₁) − K × e^(−r×T) × N(d₂)
d₁ = [ln(S/K) + (r + σ²/2) × T] / (σ × √T)
d₂ = d₁ − σ × √T
N(·) is the standard normal CDF.
Inputs: S, K, T, r, σ. Five numbers. Get any one wrong and the answer flips.
4. The Greeks (sensitivities)
| Greek | Measures sensitivity to | Intuition |
|---|---|---|
| Delta (Δ) | Underlying price | Hedge ratio — how many units of underlying to offset 1 option |
| Gamma (Γ) | Rate of change of Delta | Convexity — re-hedging frequency |
| Theta (Θ) | Time | Daily decay of time value |
| Vega (ν) | Volatility | Bigger σ → bigger option value |
| Rho (ρ) | Risk-free rate | Usually small |
Delta:
- •Long call: 0 to +1
- •Long put: −1 to 0
5. Swaps — equivalent to a strip of forwards
Most common in AFM: plain vanilla interest rate swap.
- •Party A pays fixed, receives floating.
- •Party B pays floating, receives fixed.
- •Net cash settles each period based on notional × rate differential.
Use case: Indian firm with floating-rate ECB loan swaps to fixed via a CCBS
(cross-currency basis swap) to lock its INR cost.
Currency swap = swap of principal and interest in two different currencies.
Treat the principal exchange at start and end as two forward contracts.
6. ICAI exam patterns
| Question shape | Typical marks |
|---|---|
| Put-call parity arbitrage | 4–6 |
| Binomial valuation of European call (2-period) | 8 |
| Black-Scholes computation with given d₁/d₂ tables | 6–8 |
| Hedge ratio (Delta) and dynamic re-hedging | 6 |
| Forward / futures arbitrage triangle | 6 |
| Swap valuation as PV of remaining cash flows | 6 |
Derivatives appears in almost every attempt. Total weight: 12–16 marks
across compulsory + optional questions.
7. The 60+ marks topper convention
- •Always state the convention — continuous vs simple compounding, days
in year (360 vs 365). Examiners dock for unstated assumptions.
- •Draw the option payoff diagram when asked about a strategy
(straddle, strangle, collar) — even when not strictly required. Visible
reasoning earns marks.
- •For binomial, draw the lattice — each node labelled with stock and
option value.
- •For put-call parity arbitrage, identify the action — "Buy the
underpriced call, sell the overpriced put, short the stock, invest PV of
K at r" — the four-step recipe.
- •Box the final option value / arbitrage profit.
Worked examples
Worked example 1 — Put-Call Parity arbitrage
A stock trades at ₹500. A 3-month European call with strike ₹520 trades at
₹15. A 3-month European put with the same strike trades at ₹38. Risk-free
rate is 6% p.a. (continuous compounding). Is there an arbitrage?
Step 1 — Compute parity-implied call value
C − P = S − K × e^(−r×T)
C − P = 500 − 520 × e^(−0.06 × 0.25) = 500 − 520 × 0.9851 = 500 − 512.25
C − P_parity = −12.25
So C should = P − 12.25 = 38 − 12.25 = ₹25.75
Step 2 — Compare with market
Market C = ₹15. Parity C = ₹25.75. Call is underpriced by ₹10.75.
Step 3 — Arbitrage trade
To capture the mispricing:
- Buy the underpriced call at ₹15.
- Write (sell) the put at ₹38.
- Sell short the stock at ₹500.
- Invest ₹512.25 (= 520 × e^(−0.06 × 0.25)) at 6% for 3 months.
Net cash inflow today: −15 + 38 + 500 − 512.25 = ₹10.75
At expiry, regardless of stock price, positions cancel and the ₹10.75
invested grows to ₹10.91 — riskless profit.
Final answer: Arbitrage profit = ₹10.75 today (= ₹10.91 at expiry).
Worked example 2 — One-period binomial call
Stock at ₹100. After 6 months it will be either ₹120 (u = 1.20) or ₹90
(d = 0.90). Strike ₹105. Risk-free 5% p.a. continuous.
Step 1 — Risk-neutral probability
p = (e^(r×t) − d) / (u − d) = (e^(0.05 × 0.5) − 0.90) / (1.20 − 0.90)
p = (1.02532 − 0.90) / 0.30 = 0.12532 / 0.30 = **0.4177**
Step 2 — Payoffs at expiry
- •Up: max(120 − 105, 0) = ₹15
- •Down: max(90 − 105, 0) = ₹0
Step 3 — Expected payoff under p, discount
C₀ = e^(−r×t) × [p × 15 + (1 − p) × 0]
C₀ = 0.97531 × [0.4177 × 15 + 0.5823 × 0]
C₀ = 0.97531 × 6.266 = **₹6.11**
Final answer: Theoretical call value = ₹6.11
Detailed flowcharts
Derivatives Taxonomy + Pricing Approach
Render diagram ↗flowchart TD
A[Derivative needed] --> B{Linear payoff<br/>or non-linear?}
B -->|Linear<br/>obligation| C{Customised?}
B -->|Non-linear<br/>right not obligation| D[Option]
B -->|Multi-period<br/>swap of CFs| E[Swap]
C -->|Yes — OTC| C1[Forward]
C -->|No — exchange| C2[Future]
C1 --> P1["F = S × e^r×T<br/>no-arb pricing"]
C2 --> P1
C2 --> P2[Daily MTM<br/>+ margin]
D --> D1{Call or Put?}
D1 -->|Call| D2[Right to BUY at K]
D1 -->|Put| D3[Right to SELL at K]
D2 --> O1[Payoff = max·S−K, 0]
D3 --> O2[Payoff = max·K−S, 0]
O1 --> M{Model?}
O2 --> M
M -->|European, log-normal| M1[Black-Scholes]
M -->|American or<br/>path-dependent| M2[Binomial<br/>lattice]
M -->|Quick check| M3["Put-Call parity:<br/>C − P = S − K·e^−r·T"]
E --> E1[Interest rate swap:<br/>fixed ⇄ floating]
E --> E2[Currency swap:<br/>principal + interest]
style M1 fill:#dbeafe,stroke:#1d4ed8
style M2 fill:#dbeafe,stroke:#1d4ed8
style M3 fill:#fef3c7,stroke:#b45309Pitfalls examiners flag
Common pitfalls
- Confusing American and European options. Black-Scholes assumes
European. American puts (especially on non-dividend) can be optimal to
exercise early — Black-Scholes will under-price them.
- Forgetting that intrinsic value can't be negative.
max(S − K, 0)
not just S − K. Easy to write the wrong thing on a 2 AM revision.
- Mixing up which side pays the premium. The buyer of an option pays
premium and has the right. The writer receives premium and has the
obligation.
- Using simple compounding in Black-Scholes. The formula assumes
continuous compounding (e^(−rT) discount). If the problem gives a simple
rate, convert first.
- Put-call parity with American options. Strict equality only holds for
European. American puts trade at a premium to the parity-implied value —
know this.
- Forgetting margin in futures. Futures pricing arbitrage assumes you
can carry the position. Daily MTM + margin calls can force closure
before convergence — practical issue cited in case-study questions.
30-second revision card
Derivatives — 30-second recap
- •F = S × e^(r×T) (no-arb forward)
- •Call payoff = max(S−K, 0), Put = max(K−S, 0)
- •Put-call parity: C − P = S − K·e^(−r×T)
- •Black-Scholes: C = S·N(d₁) − K·e^(−r×T)·N(d₂)
- •Binomial p = (e^(r×t) − d)/(u − d) — risk-neutral
- •Greeks: Δ (price), Γ (Δ-change), Θ (time decay), ν (vol), ρ (rate)
- •Swap = strip of forwards; CCBS for FX
- •Always state compounding convention and days-in-year
Make it click