CQF Comprehensive Cheatsheet - FX Module

Foreign Exchange: Spot, Forwards, Options, Volatility Surfaces & Exotic Products

FX MARKET FUNDAMENTALS

Currency Pair Conventions

Quote Convention: CCY1/CCY2 = "how many units of CCY2 per 1 unit of CCY1"

  • Base currency (CCY1): Denominator in exchange rate
  • Quote/counter currency (CCY2): Numerator
  • Example: EUR/USD = 1.10 means €1 = $1.10

Major Pairs:

  • EUR/USD (Euro/US Dollar) - "Euro"
  • USD/JPY (US Dollar/Japanese Yen) - "Dollar Yen"
  • GBP/USD (British Pound/US Dollar) - "Cable"
  • AUD/USD (Australian Dollar/US Dollar) - "Aussie"
  • USD/CHF (US Dollar/Swiss Franc) - "Swissy"
  • USD/CAD (US Dollar/Canadian Dollar) - "Loonie"

Inverted Rates:

$$\text{USD/EUR} = \frac{1}{\text{EUR/USD}}$$
Example: If EUR/USD = 1.1000, then USD/EUR = 1/1.1000 = 0.9091

Bid-Ask Spreads

Bid: Price at which dealer buys base currency (sells quote currency)

Ask/Offer: Price at which dealer sells base currency (buys quote currency)

Market Quote: EUR/USD = 1.1000/1.1003
Dealer buys EUR at 1.1000, sells EUR at 1.1003
Spread = 3 pips (1 pip = 0.0001 for most pairs)

Pip: "Percentage in point" or "Price interest point"

  • Most pairs: 0.0001 (4th decimal)
  • JPY pairs: 0.01 (2nd decimal)
  • Pipette: 1/10 of a pip (fractional pip)

Cross Rates

Definition: Exchange rate between two currencies, neither of which is USD

Calculation via USD:

$$\frac{\text{EUR}}{\text{GBP}} = \frac{\text{EUR/USD}}{\text{GBP/USD}}$$
Example: EUR/USD = 1.1000, GBP/USD = 1.2500
EUR/GBP = 1.1000/1.2500 = 0.8800
(€1 = £0.88)

Triangular Arbitrage: Profit from inconsistent cross rates

$$S_{AC} \neq \frac{S_{AB}}{S_{CB}} \implies \text{Arbitrage opportunity}$$

SPOT FX MARKET

Spot Rate

Definition: Exchange rate for immediate delivery

Settlement: T+2 (two business days) for most pairs

Exceptions:

  • USD/CAD: T+1
  • Some exotic pairs: T+2 or longer

Value Date: Date on which currencies are actually exchanged

FX Dynamics under GBM

Spot rate \(S_t\) (domestic/foreign) follows:

$$dS_t = (r_d - r_f) S_t dt + \sigma S_t dW_t$$

where:

  • \(r_d\) = domestic interest rate
  • \(r_f\) = foreign interest rate
  • \(\sigma\) = FX volatility
  • \(r_d - r_f\) = drift under domestic risk-neutral measure

Interpretation: Foreign currency is like a dividend-paying stock with yield \(r_f\)

Interest Rate Parity

Covered Interest Rate Parity (CIRP):

$$F = S \cdot \frac{1 + r_d T}{1 + r_f T}$$

Or in continuous compounding:

$$F = S \cdot e^{(r_d - r_f)T}$$

No-arbitrage condition: Forward price equals expected future spot

Example: EUR/USD spot = 1.1000, \(r_{USD} = 2\%\), \(r_{EUR} = 0.5\%\), \(T = 1\) year
\(F = 1.1000 \times e^{(0.02 - 0.005) \times 1} = 1.1000 \times e^{0.015} = 1.1166\)
Euro trades at forward premium (higher rate currency depreciates)

Uncovered Interest Rate Parity (UIRP):

$$\mathbb{E}[S_{t+T}] = S_t \cdot e^{(r_d - r_f)T}$$

Expected spot movement equals interest differential
Empirically violated: "Forward premium puzzle"


FX FORWARDS AND SWAPS

Forward Contracts

Definition: Agreement to exchange currencies at future date \(T\) at predetermined rate \(F\)

Forward Rate:

$$F(t,T) = S_t \cdot e^{(r_d - r_f)(T-t)}$$

Forward Points (swap points):

$$\text{FP} = F - S$$

Quoted in pips, added to spot rate

Example: Spot EUR/USD = 1.1000, 1Y forward points = +166
1Y Forward = 1.1000 + 0.0166 = 1.1166

Premium/Discount:

  • \(r_d > r_f\): Foreign currency at forward premium (\(F > S\))
  • \(r_d < r_f\): Foreign currency at forward discount (\(F < S\))

Forward P&L

Long forward (agree to buy base currency at \(F\)):

At maturity \(T\):

$$\text{P\&L} = (S_T - F) \times \text{Notional}$$

Before maturity at time \(t < T\):

$$\text{MTM} = (F(t,T) - F) \times \text{Notional} \times e^{-r_d(T-t)}$$
Example: Long 1Y EUR/USD forward at \(F = 1.1166\), notional €10M
After 6 months: Spot = 1.1500, new 6M forward = 1.1583
MTM = (1.1583 - 1.1166) × 10M × \(e^{-0.02 \times 0.5}\)
= 0.0417 × 10M × 0.99 = $412,800 profit

FX Swaps

Definition: Simultaneous spot and forward transactions in opposite directions

Typical structure:

  1. Spot leg: Buy EUR/sell USD at spot \(S\)
  2. Forward leg: Sell EUR/buy USD at forward \(F\)

Swap Points:

$$\text{Swap Points} = (F - S) \times \text{Notional}$$

Purpose:

  • Roll FX positions
  • Funding in foreign currency
  • Manage maturity mismatches

Cross-Currency Basis: Deviation from theoretical forward due to:

  • Supply/demand imbalances
  • Credit risk differences
  • Regulatory costs
$$F_{market} = F_{theory} + \text{Basis}$$
Post-2008 Crisis: CIP violations common. USD funding premium led to persistent cross-currency basis, especially in EUR/USD, JPY/USD. "Basis swaps" actively traded.

FX OPTIONS - VANILLA

Garman-Kohlhagen Model

FX Option Pricing (extension of Black-Scholes for FX):

Call Option (right to buy base currency):

$$C = S_0 e^{-r_f T} N(d_1) - K e^{-r_d T} N(d_2)$$ $$d_1 = \frac{\ln(S_0/K) + (r_d - r_f + \sigma^2/2)T}{\sigma\sqrt{T}}$$ $$d_2 = d_1 - \sigma\sqrt{T}$$

Put Option (right to sell base currency):

$$P = K e^{-r_d T} N(-d_2) - S_0 e^{-r_f T} N(-d_1)$$

Put-Call Parity:

$$C - P = S_0 e^{-r_f T} - K e^{-r_d T}$$

Or equivalently:

$$C - P = (F - K) e^{-r_d T}$$
Example: EUR/USD option, \(S = 1.10\), \(K = 1.12\), \(T = 0.25\), \(\sigma = 10\%\)
\(r_{USD} = 2\%\), \(r_{EUR} = 0.5\%\)

\(d_1 = \frac{\ln(1.10/1.12) + (0.02-0.005+0.005)0.25}{0.10\sqrt{0.25}} = -0.2851\)
\(d_2 = -0.2851 - 0.05 = -0.3351\)
\(N(d_1) = 0.3877\), \(N(d_2) = 0.3687\)

\(C = 1.10 \times e^{-0.005 \times 0.25} \times 0.3877 - 1.12 \times e^{-0.02 \times 0.25} \times 0.3687\)
\(= 0.4261 - 0.4110 = \boxed{0.0151}\) or 151 pips

FX Option Greeks

Delta \(\Delta = \frac{\partial V}{\partial S}\):

  • Call: \(\Delta = e^{-r_f T} N(d_1) \in [0, e^{-r_f T}]\)
  • Put: \(\Delta = -e^{-r_f T} N(-d_1) \in [-e^{-r_f T}, 0]\)
  • ATM call delta ≈ 0.5 × \(e^{-r_f T}\) (adjusted for foreign rate)

Gamma \(\Gamma = \frac{\partial^2 V}{\partial S^2}\):

$$\Gamma = \frac{e^{-r_f T} N'(d_1)}{S \sigma \sqrt{T}}$$

Same for calls and puts

Vega \(\mathcal{V} = \frac{\partial V}{\partial \sigma}\):

$$\mathcal{V} = S e^{-r_f T} \sqrt{T} N'(d_1)$$

Theta \(\Theta = \frac{\partial V}{\partial t}\):

Call:

$$\Theta_C = -\frac{S e^{-r_f T} N'(d_1) \sigma}{2\sqrt{T}} + r_f S e^{-r_f T} N(d_1) - r_d K e^{-r_d T} N(d_2)$$

Rho (dual sensitivities):

  • \(\rho_d = \frac{\partial V}{\partial r_d}\): Sensitivity to domestic rate
  • \(\rho_f = \frac{\partial V}{\partial r_f}\): Sensitivity to foreign rate

Call: \(\rho_d = KT e^{-r_d T} N(d_2)\), \(\rho_f = -ST e^{-r_f T} N(d_1)\)

Option Quoting Conventions

Delta Convention: Options quoted by delta, not strike

  • 25-delta call: Call with \(\Delta = 0.25 e^{-r_f T}\)
  • 25-delta put: Put with \(|\Delta| = 0.25 e^{-r_f T}\)
  • ATM: At-the-money (strike ≈ forward)

Strike from Delta (for call):

$$K = S e^{(r_d - r_f)T - \sigma\sqrt{T} N^{-1}(\Delta e^{r_f T}) + \sigma^2 T/2}$$

ATM Strike Conventions:

  • ATM DNS (Delta-Neutral Straddle): \(K\) where call delta + put delta = 0
  • ATM Forward: \(K = F\)
  • ATM Spot: \(K = S\)

Most liquid: ATM DNS (50-delta straddle)


FX VOLATILITY SURFACE

Volatility Smile

Implied Volatility \(\sigma_{imp}(K,T)\): Volatility that equates model price to market price

FX Smile Characteristics:

  • Symmetric smile: Higher vol for OTM puts and calls
  • Risk reversals: Measure of skew
  • Butterflies: Measure of curvature (smile vs flat)
Market Quotes (for given maturity):
  • ATM volatility: Vol of ATM straddle
  • 25Δ Risk Reversal (RR): \(\sigma_{25Δ Call} - \sigma_{25Δ Put}\)
  • 25Δ Butterfly (BF): \(\frac{\sigma_{25Δ Call} + \sigma_{25Δ Put}}{2} - \sigma_{ATM}\)

Recovering Individual Vols:

$$\sigma_{25Δ Call} = \sigma_{ATM} + \frac{RR}{2} + BF$$ $$\sigma_{25Δ Put} = \sigma_{ATM} - \frac{RR}{2} + BF$$
Example: 1M EUR/USD options
ATM = 10%, 25Δ RR = 1.5%, 25Δ BF = 0.3%

\(\sigma_{25Δ Call} = 10\% + 0.75\% + 0.3\% = 11.05\%\)
\(\sigma_{25Δ Put} = 10\% - 0.75\% + 0.3\% = 9.55\%\)

Positive RR → call vol > put vol (bullish skew)

Vega-Weighted Smile

Why vega weights? Market measures smile by vega-weighted prices, not vol difference

Strangle (25Δ call + 25Δ put):

$$\text{Strangle Price} = C_{25Δ} + P_{25Δ}$$

Market BF relates to strangle price vs ATM straddle:

$$BF \approx \frac{\text{Strangle}_{\text{mid}} - 2 \times \text{ATM}_{\text{price}}}{\text{Vega}}$$

Volatility Term Structure

Vol vs Maturity: \(\sigma(T)\) typically follows patterns:

  • Short end (< 1M): Higher vol (event risk, liquidity)
  • Medium term (1M-1Y): Intermediate vol
  • Long end (>1Y): Lower vol (mean reversion)

Vol interpolation:

  • Linear in variance: \(\sigma^2(T)\)
  • Avoid calendar arbitrage

Sticky Delta vs Sticky Strike

Sticky Strike: Vol surface fixed in strike space

  • When spot moves, delta of option changes

Sticky Delta: Vol surface fixed in delta space

  • When spot moves, implied vol adjusts to maintain delta

Reality: FX markets mostly sticky delta


EXOTIC FX OPTIONS

Digital (Binary) Options

Cash-or-Nothing Call: Pays fixed amount \(Q\) if \(S_T > K\)

$$V = Q e^{-r_d T} N(d_2)$$

Asset-or-Nothing Call: Pays \(S_T\) if \(S_T > K\)

$$V = S e^{-r_f T} N(d_1)$$

Delta of cash-or-nothing call:

$$\Delta = \frac{Q e^{-r_d T} N'(d_2)}{\sigma S \sqrt{T}}$$

Spikes at maturity if near strike (gamma risk)

Barrier Options

Types:

  • Knock-Out: Option dies if barrier hit
  • Knock-In: Option activated if barrier hit
  • Up: Barrier above spot
  • Down: Barrier below spot
Type Barrier Condition Use Case
Up-and-Out (UOC) \(H > S\) KO if \(S_t \geq H\) Cheaper call, limited upside view
Down-and-Out (DOC) \(H < S\) KO if \(S_t \leq H\) Cheaper call, bullish view
Up-and-In (UIC) \(H > S\) Activated if \(S_t \geq H\) Bet on break above level
Down-and-In (DIC) \(H < S\) Activated if \(S_t \leq H\) Protection after dip

In-Out Parity:

$$\text{Barrier In} + \text{Barrier Out} = \text{Vanilla}$$

Approximate pricing (down-and-out call, \(H < S < K\)):

$$C_{DOC} \approx C_{vanilla} - \left(\frac{H}{S}\right)^{2\lambda} C(K', H^2/S)$$

where \(\lambda = \frac{r_d - r_f + \sigma^2/2}{\sigma^2}\), \(K' = H^2/K\)

Example: EUR/USD spot = 1.10, UOC strike = 1.15, barrier = 1.20
Vanilla call = 0.0200 (200 pips)
UOC ≈ 0.0150 (150 pips) - cheaper due to knockout
Rebate (payment if knocked out) can be added for compensation

Greeks peculiarities:

  • Delta can flip sign as spot approaches barrier
  • Large gamma near barrier
  • Vega can be negative for out-of-money barriers

Asian Options

Payoff: Based on average exchange rate over period

Arithmetic Average:

$$\text{Payoff} = \max\left(\bar{S} - K, 0\right), \quad \bar{S} = \frac{1}{n}\sum_{i=1}^n S_{t_i}$$

No closed form, use Monte Carlo or PDE

Geometric Average:

$$\bar{S}_G = \left(\prod_{i=1}^n S_{t_i}\right)^{1/n}$$

Closed-form exists (log-normal distribution of geometric average)

Properties:

  • Lower volatility than vanilla (averaging effect)
  • Cheaper premium
  • Used for hedging regular FX flows

Lookback Options

Floating Strike Call:

$$\text{Payoff} = S_T - S_{min}$$

Guarantees best possible price (buying at lowest level)

Fixed Strike:

$$\text{Payoff} = \max(S_{max} - K, 0)$$

Expensive (hindsight perfection) but popular for structured products

Touch Options

One-Touch: Pays if spot touches barrier before expiry

  • Digital with continuous monitoring

No-Touch: Pays if spot never touches barrier

  • One-Touch + No-Touch = Present Value of payment

Double-No-Touch (DNT): Pays if spot stays within corridor \([L, U]\)

  • Used for range-bound views
Example: 1M EUR/USD DNT, \(L = 1.08\), \(U = 1.12\), current = 1.10
Payment = $100k if spot stays in range
Implied probability ≈ 60% (from pricing)
Payout (PV) = 100k × 0.60 × \(e^{-rT}\) ≈ $59.7k

Target Redemption Forwards (TRF/TARF)

Structure: Series of forwards that terminates when cumulative profit reaches target

Features:

  • Participation ratio: Asymmetric (e.g., 1:2 leverage on wrong side)
  • Knockout level: Target profit
  • Popular in Asia (controversial due to client losses)

Risk: Unlimited loss potential with capped gains


FX VOLATILITY MODELING

Stochastic Volatility Models

Heston Model for FX:

$$dS_t = (r_d - r_f) S_t dt + \sqrt{v_t} S_t dW_t^S$$ $$dv_t = \kappa(\theta - v_t)dt + \xi\sqrt{v_t} dW_t^v$$ $$dW_t^S dW_t^v = \rho dt$$

Negative \(\rho\) typical in FX (higher vol when currency depreciates)

Calibration: Fit to market smile (ATM, RR, BF)

Local Volatility Models

Dupire Formula:

$$\sigma_{local}^2(K,T) = \frac{\frac{\partial C}{\partial T} + (r_d - r_f) K \frac{\partial C}{\partial K} + r_d C}{\frac{1}{2}K^2 \frac{\partial^2 C}{\partial K^2}}$$

Constructs volatility surface \(\sigma(S,t)\) consistent with market prices

Properties:

  • Perfectly fits market vanilla options
  • Deterministic volatility path (given spot path)
  • Poor forward smile dynamics

SABR Model for FX

Dynamics:

$$dF_t = \alpha_t F_t^\beta dW_t^F$$ $$d\alpha_t = \nu \alpha_t dW_t^\alpha$$ $$dW_t^F dW_t^\alpha = \rho dt$$

Market standard: \(\beta = 0.5\) or \(\beta = 1\) (lognormal)

Implied Vol Approximation (Hagan et al.):

For \(K \approx F\) (ATM):

$$\sigma_{BS} \approx \frac{\alpha}{F^{1-\beta}}\left[1 + \left(\frac{(1-\beta)^2}{24}\frac{\alpha^2}{F^{2-2\beta}} + \frac{\rho\beta\nu\alpha}{4F^{1-\beta}} + \frac{2-3\rho^2}{24}\nu^2\right)T\right]$$

Calibration to market quotes:

  1. Use ATM vol to constrain \(\alpha\)
  2. Use RR to fit \(\rho\) (skew)
  3. Use BF to fit \(\nu\) (vol-of-vol, curvature)

FX RISK MANAGEMENT

Delta Hedging

Delta-Neutral Portfolio:

$$\text{Position} = V - \Delta \times S$$

where \(\Delta = \frac{\partial V}{\partial S} \times \text{Notional}\)

Rebalancing frequency: Balance between transaction costs and hedge effectiveness

Example: Short 10M EUR/USD call, delta = 0.50
Delta hedge: Buy 0.50 × €10M = €5M spot
If spot moves from 1.10 → 1.11, new delta = 0.55
Additional hedge: Buy 0.05 × €10M = €500k

Vega Hedging

Vega-Neutral: Offset volatility exposure with opposite vega position

Common approach: Hedge with ATM options (highest vega)

$$\text{Hedge Ratio} = \frac{\mathcal{V}_{portfolio}}{\mathcal{V}_{hedge instrument}}$$

Value-at-Risk for FX

Parametric VaR (normal returns):

$$\text{VaR}_\alpha = \text{Position} \times \sigma \sqrt{\Delta t} \times z_\alpha$$
Example: Position = €10M (long), \(\sigma = 10\%\) p.a., 10-day horizon
\(\text{VaR}_{99\%} = 10M \times 0.10 \times \sqrt{10/252} \times 2.33\)
= 10M × 0.0198 × 2.33 = €462k

Historical Simulation: Apply historical returns to current position

Monte Carlo: Simulate future spot paths, calculate P&L distribution

Currency Exposure Types

Exposure Type Description Hedge Strategy
Transaction Known future cash flow Forward contract
Translation Foreign subsidiary balance sheet Balance sheet hedge (debt)
Economic Competitive position vs FX Natural hedge, derivatives

FX CARRY TRADE

Carry Trade Mechanics

Strategy:

  1. Borrow in low-interest currency (funding currency)
  2. Invest in high-interest currency (target currency)
  3. Profit from interest differential

Carry:

$$\text{Carry} = r_{high} - r_{low}$$

Total Return (unhedged):

$$R = (r_{high} - r_{low}) + \frac{\Delta S}{S}$$

where \(\frac{\Delta S}{S}\) is target currency appreciation

Example: Borrow JPY (0.5%), invest in AUD (4.5%)
Carry = 4.5% - 0.5% = 4.0% p.a.
If AUD/JPY unchanged: Return = 4.0%
If AUD appreciates 2%: Return = 4.0% + 2.0% = 6.0%
If AUD depreciates 5%: Return = 4.0% - 5.0% = -1.0%

Risk:

  • Funding currency appreciation (wipes out carry)
  • Crashes during risk-off events (2008, COVID)
  • High kurtosis (fat tails)

Forward Premium Puzzle: Empirically, high-interest currencies tend to appreciate (violates UIRP)

Carry-to-Risk Ratio

$$\text{Sharpe Ratio} = \frac{\text{Carry}}{\sigma_{FX}}$$

Higher ratio = better risk-adjusted carry

Crowded Carry Unwind

2008 Crisis: JPY carry trades unwound violently

  • USD/JPY: 110 → 87 (-21%)
  • AUD/JPY: 107 → 55 (-49%)
  • Liquidation spiral: Losses → margin calls → more unwinding

FX MARKET MICROSTRUCTURE

Order Flow and Price Discovery

Order Flow: Net buying pressure (buy orders - sell orders)

Empirical finding: Order flow strongly predicts short-term FX movements

Price impact:

$$\Delta S \propto \text{Order Flow} \times \sqrt{\text{Volume}}$$

FX Market Participants

  • Interbank market: Banks trading with each other
  • Prime brokers: Provide access to hedge funds
  • Electronic platforms: EBS, Reuters Matching, FXall
  • Corporates: Hedging commercial flows
  • Central banks: Intervention, reserves management
  • Retail: Via brokers, typically small size

Trading Sessions

  • Asian session: Tokyo, Singapore, Hong Kong (00:00-09:00 GMT)
  • European session: London, Frankfurt (08:00-17:00 GMT)
  • US session: New York (13:00-22:00 GMT)
  • Overlap: London-NY (13:00-17:00 GMT) - highest liquidity

Volatility patterns: Highest during overlaps, lowest during Asian afternoon

Fixing Rates

WM/Reuters Fix: 4pm London benchmark

  • Based on order flow in 1-minute window
  • Used for fund valuations, index rebalancing
  • Can cause volatility spikes

Manipulation scandals (2013-2014): Banks colluded to move fixing rates


CENTRAL BANK INTERVENTION

Types of Intervention

Direct Intervention: Central bank trades FX in market

  • Sterilized: Offset with domestic bonds (no money supply change)
  • Unsterilized: Changes monetary base

Verbal Intervention: "Jawboning" - statements to influence expectations

Effectiveness

Short-term: Can move market temporarily

Long-term: Limited if fighting fundamental trends

Famous cases:

  • Swiss National Bank (2011-2015): EUR/CHF floor at 1.20
  • Bank of Japan: Frequent interventions in USD/JPY
  • Plaza Accord (1985): G5 coordination to weaken USD

KEY FORMULAS SUMMARY

Concept Formula
Forward Rate (continuous) \(F = S \cdot e^{(r_d - r_f)T}\)
Spot Dynamics \(dS = (r_d - r_f)S dt + \sigma S dW\)
Call Option (GK) \(C = Se^{-r_fT}N(d_1) - Ke^{-r_dT}N(d_2)\)
Put-Call Parity \(C - P = Se^{-r_fT} - Ke^{-r_dT}\)
Call Delta \(\Delta_C = e^{-r_fT}N(d_1)\)
Gamma \(\Gamma = \frac{e^{-r_fT}N'(d_1)}{S\sigma\sqrt{T}}\)
Vega \(\mathcal{V} = Se^{-r_fT}\sqrt{T}N'(d_1)\)
25Δ Call Vol \(\sigma_{ATM} + \frac{RR}{2} + BF\)
25Δ Put Vol \(\sigma_{ATM} - \frac{RR}{2} + BF\)
Carry Return \(R = (r_{high} - r_{low}) + \frac{\Delta S}{S}\)

COMMON MISTAKES & TIPS

Common Mistakes:
  1. Wrong currency pair convention: EUR/USD = 1.10 means €1 = $1.10, not $1 = €1.10
  2. Confusing base/quote: In EUR/USD, EUR is base, USD is quote
  3. Delta adjustment for foreign rate: ATM delta ≈ 0.5\(e^{-r_fT}\), not 0.5
  4. Forward points: Add to spot, don't multiply
  5. Forgetting foreign rate in pricing: Use \(r_d - r_f\), not just \(r_d\)
  6. Sign of delta: Put delta is negative
  7. Barrier direction: Down-and-out means barrier below spot
  8. RR interpretation: Positive RR = call vol > put vol (not necessarily bullish)
Quick Interview Tips:
  • Why FX smile symmetric? Both currencies are "risky" (unlike equity/zero)
  • Sticky delta: FX market convention (vs equity sticky strike)
  • Carry trade risk: "Picking up nickels in front of a steamroller"
  • Put-call parity: Forward position = Long call + Short put
  • High yield currencies: Tend to depreciate on average (UIRP), but not always
  • Triangular arbitrage: Cross rates must be consistent
  • CIP violations post-2008: Cross-currency basis widened significantly
  • Most liquid pairs: EUR/USD > USD/JPY > GBP/USD
  • Bid-ask spread: Lower for majors (1-3 pips), higher for exotics (10-50 pips)
  • FX fixes: Can create manipulation opportunities (WM/Reuters scandal)

PRACTICAL EXAMPLE: COMPLETE OPTION PRICING

Real-World FX Option Pricing Example:

Market Data:
  • Spot EUR/USD = 1.1000
  • EUR interest rate = 0.50% p.a.
  • USD interest rate = 2.00% p.a.
  • Maturity = 3 months (T = 0.25)
  • Volatility structure:
    • ATM vol = 10.0%
    • 25Δ Risk Reversal = 1.5%
    • 25Δ Butterfly = 0.3%
Task 1: Price ATM call

Forward rate: \(F = 1.1000 \times e^{(0.02-0.005) \times 0.25} = 1.1041\)
ATM strike (DNS): \(K \approx F = 1.1041\)

Using Garman-Kohlhagen with \(\sigma = 10\%\):
\(d_1 = \frac{\ln(1.1000/1.1041) + (0.02-0.005+0.005) \times 0.25}{0.10 \times 0.5} = 0.0256\)
\(d_2 = 0.0256 - 0.05 = -0.0244\)
\(N(d_1) = 0.5102\), \(N(d_2) = 0.4903\)

\(C = 1.1000 \times e^{-0.005 \times 0.25} \times 0.5102 - 1.1041 \times e^{-0.02 \times 0.25} \times 0.4903\)
\(= 0.5597 - 0.5387 = \boxed{0.0210}\) or 210 pips

Task 2: Construct volatility smile

\(\sigma_{25Δ \text{ Call}} = 10.0\% + \frac{1.5\%}{2} + 0.3\% = 11.05\%\)
\(\sigma_{25Δ \text{ Put}} = 10.0\% - \frac{1.5\%}{2} + 0.3\% = 9.55\%\)

Task 3: Find 25Δ call strike

For call delta = \(0.25 \times e^{-0.005 \times 0.25} = 0.2497\):
Using iterative solver (or approximation):
\(K_{25Δ \text{ Call}} \approx 1.1350\)

Task 4: Price 25Δ call with smile vol

Using \(\sigma = 11.05\%\) (instead of flat 10%):
\(C_{25Δ} \approx \boxed{0.0092}\) or 92 pips

Task 5: Delta hedge

Notional = €10M
ATM call delta = 0.5102 × \(e^{-0.005 \times 0.25}\) = 0.5096
Hedge: Buy €5.096M spot at 1.1000
USD amount: 5.096M × 1.10 = $5.606M

Task 6: P&L after 1 week

Assume spot moves to 1.1100, vol unchanged:
New option value ≈ 0.0320 (320 pips)
Spot P&L = 5.096M × (1.1100 - 1.1000) = €0.051M
Option P&L = (0.0320 - 0.0210) × 10M = €0.110M
Total = €0.110M - €0.051M × 1.11 = €0.053M profit
(Positive due to gamma - delta hedge slightly underhedged)