FRAs, rate futures and convexity
Locking a forward fixing while separating settlement timing and futures convexity
01Price an FRA from projected fixing and discounting.
02Derive the standard settlement-in-advance denominator.
03Explain why a daily-margined futures quote differs from a forward rate.
04Map front-end curve shocks into FRA and futures P&L.
Read the cash-flow timeline first.
A forward rate agreement exchanges the difference between a contracted rate and a future fixing. Futures trade a related exposure but settle variation margin daily, creating a covariance effect between rates and reinvestment.
FRA value needs both projection and discounting.
Settlement timing changes the payoff denominator.
Futures equals forward only when daily-margin covariance is negligible.
Start from cash flows and quotation.
FRAs and rate futures are the liquid building blocks for forward-curve construction, central-bank path trading and front-end hedging.
forward rate agreements
three-month rate futures
OIS futures
forward-start swaps
State index, fixing period, accrual basis, settlement timing and whether the market price is quoted as 100 minus rate.
Value each dated cash flow under explicit conventions.
End-settled FRA PV
Projected coupon difference discounted from the payment date.
Open in AnalyticsStart-settled FRA payoff
The end-period interest difference is discounted back to the fixing/start date.
Open in AnalyticsShort derivation
From a future deposit to an FRA payoff
Compare the interest on a deposit struck at K with one struck at the future observed rate.
- 01
Define the accrual-period interest
On notional N, the interest difference paid at T₂ is Nδ(L−K).
- 02
Settle in advance if required
Discount that difference from T₂ to T₁ using the realised deposit rate L.
- 03
Value before fixing
Replace the unknown fixing with its projection under the appropriate curve and discount the resulting cash flow.
- 04
Separate futures margining
Daily variation margin is reinvested at stochastic rates; estimate the covariance correction with a stated rate model.
FRA and futures quotes target similar forward exposure but differ through settlement mechanics and convexity.
Inputs
F: projected simple fixingK: contractual rateδ: accrual fractionD: settlement discount factor
Assumptions and limits
- Convexity adjustment is model and volatility dependent.
- Exchange contract dates may not align with OTC tenors.
- Fallback index conventions can alter legacy FRA economics.
Futures-forward adjustment
Daily margining adds a model-dependent covariance correction.
Open in AnalyticsBuild, calibrate, and reprice the contract.
Project the index fixing, apply exact payoff timing and discounting, then add a separately governed futures-convexity adjustment when mapping exchange quotes.
Use liquid futures with price, expiry, delivery period and convexity assumptions; repricing must be reported before and after the adjustment.
Implementation with current QuantLib
Use the relevant IborIndex or overnight-index futures helper, contract-specific dates and a documented convexity adjustment. Keep futures price conversion separate from forward-rate projection.
API authority: upstream QuantLib reference pinned in the source registry.06PYTHON IMPLEMENTATIONOpen the implementation and checks.
- Parse dated market inputs and conventions at the boundary.
- Build deterministic curve objects in the framework-free quant layer.
- Return PV, repricing residuals and sensitivities together.
- Test inversion, par conditions, monotonic dates and invalid domains.
FRA zero-PV and settlement check
Verify the par condition and settlement-in-advance payoff.
from __future__ import annotations def fra_start_payoff(notional: float, fixing: float, strike: float, accrual: float) -> float: denominator = 1.0 + accrual * fixing if notional < 0 or accrual <= 0 or denominator <= 0: raise ValueError("invalid FRA domain") return notional * accrual * (fixing - strike) / denominator notional, forward, accrual = 10_000_000.0, 0.0435, 0.25assert fra_start_payoff(notional, forward, forward, accrual) == 0.0up = fra_start_payoff(notional, forward + 0.0001, forward, accrual)assert 240.0 < up < 250.0print(f"+1bp fixing payoff={up:.2f}")Move the state. Challenge the equation.
FRA/futures convexity laboratory
Move rate volatility, correlation and settlement timing; compare forward, futures and FRA PV.
Low volatility: Forward and futures nearly coincide.
- forward rate
- futures-equivalent
Use Left/Right or Up/Down arrows to inspect values; Home and End jump to the bounds.
Follow the trade through risk and lifecycle events.
“A futures strip is a policy view plus a margining convention plus a convexity assumption.”
contract dates
index curve
discount curve
accrual basis
volatility/correlation adjustment
Use liquid futures with price, expiry, delivery period and convexity assumptions; repricing must be reported before and after the adjustment.
RISKmeeting-date risk
convexity
roll and delivery risk
basis to OTC
- map exchange dates
- convert price to rate
- apply convexity
- bootstrap forward
- hedge residual basis
Production failure modes
- wrong IMM date
- price/rate sign error
- silent zero convexity
- misaligned settlement timing
09MACRO CONNECTIONOpen the transmission channel.
Policy surprises in futures strips
A policy surprise reprices meeting-dated forward periods first; volatility and rate-level changes also alter the futures-forward convexity adjustment.
transmitsshifts expected fixings
transmitsreprices meeting periods
transmitstranslates futures to forwards
outputrealises basis and hedge P&L
10COMMON PITFALLSOpen the failure checklist.
Reading 100-price with the wrong sign.
Treating futures and forwards as identical.
Omitting the settlement-in-advance denominator.
Hedging OTC dates with exchange contracts without basis attribution.
11SOURCES / FURTHER READINGOpen sources and continue the track.
Interest-rate products, term structures and short-rate lectures
Research map for the rates progression and numerical experiments; all platform prose and code are original.
- Source
- Financial Engineering: Interest Rates & xVA
- Author
- L. A. Grzelak
- Ref
- main
Stochastic processes, Monte Carlo and model-calibration lectures
Mathematical cross-reference for stochastic dynamics and implementation checks.
- Source
- Computational Finance Course
- Author
- L. A. Grzelak
- Ref
- main
Current term structures, indexes, rate helpers, instruments, engines and tests
Implementation authority for production abstractions; Academy derives the mathematics before introducing library objects.
- Source
- QuantLib upstream
- Author
- QuantLib contributors
- Ref
- v1.42.1