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IRpractitionerinstrument

OIS

Fixed-versus-compounded overnight indexed swaps.

Reviewed 2026-08-10TheQuantBateman ResearchReading note
01Intuition

Build the mental model first.

OIS exchanges a fixed rate for realised compounded overnight funding.

ONE-LINE DEFINITION

Fixed-versus-compounded overnight indexed swaps.

02Mathematics

Now make it exact.

PVfixed=PVcompounded overnightPV_{fixed}=PV_{compounded\ overnight}
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.

Core collateral discounting and overnight-rate exposure.

IntuitionMathematicsImplementationDesk risk
05Desk view
FRONT OFFICE VIEW

The hedge has opinions.

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

Ask Bateman about this model
06Related

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