TQBTHEQUANTBATEMAN
TQB/ learn/ fx/ fx spotEN · DARK
FXfoundationinstrument

FX Spot

The exchange rate for near-immediate delivery between two currencies.

Reviewed 2026-08-10TheQuantBateman Research2 linked labs
01Intuition

Build the mental model first.

An FX rate is always one currency priced in another; the direction matters before any arithmetic begins.

ONE-LINE DEFINITION

The exchange rate for near-immediate delivery between two currencies.

02Mathematics

Now make it exact.

St=units of domestic currency per unit of foreign currencyS_t = \text{units of domestic currency per unit of foreign currency}
Notation and units

Decimal rates and volatilities, year-fraction time and continuous compounding unless stated otherwise.

03Assumptions

Every model has a price.

01

Educational conventions are stated explicitly and may simplify market quotation or settlement details.

02

Rates are continuously compounded unless the section says otherwise.

03

Inputs are deterministic in the base model.

“An unstated convention is a future reconciliation break.”— THEQUANTBATEMAN
04Market use

Why a quant cares.

Anchor for forwards, swaps, options and cross-currency exposures.

IntuitionMathematicsImplementationDesk risk
05Desk view
FRONT OFFICE VIEW

The hedge has opinions.

Start with the quote convention, then ask which FX risk survives the hedge. A number without its convention is merely well-dressed ambiguity.

Ask Bateman about this model
06Related

Continue through the graph.