Forex glossary
London Fix (4PM Fix)
The London fix usually refers to WMR Closing Spot Rates at 4pm London time. It is calculated from validated market data in a window around the fixing under the relevant currency methodology. It is a valuation or contractual execution benchmark, not a price guaranteed for every retail order.
Illustrative example
How does it work in practice?
Suppose a fictional agreement values 10,000 EUR at a WMR benchmark of 1.1000 USD per EUR. The value is 11,000 USD before contractual charges; a separate brokerage order may execute at another price.
A case to work through
Benchmark and execution
A fictional contract uses WMR mid 1.1000 USD per EUR; a separate broker purchase uses ask 1.1003.
- The contract values 10,000 EUR at 11,000 USD.
- The separate ask purchase costs 11,003 USD before other charges.
What follows? Do not call the difference an error without checking both agreements.
Example boundary: These are separate valuation rules, not a price guarantee.
Benchmark and separate purchase
Text description of the diagram
- WMR mid: Fictional contract: 1.1000 USD per EUR.
- Broker ask: Separate purchase: 1.1003 USD per EUR.
- 10,000 EUR: 11,000 or 11,003 USD before additional charges.
A useful distinction
London Fix (4PM Fix) / London Session
The London session is an activity window; the fix is a specified benchmark and time.
Check your understanding
Match a benchmark to a hypothetical contract.
Show the answer and explanation
No, rate types and agreements differ
A benchmark does not set every execution.
Sessions, time zones and breaks
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Related terms
Sources and documentation
- WMR FX Benchmarks Methodology – FTSE Russell
Describes the 4pm London benchmark, rate types and validated methodological inputs.
Document read: - When do the clocks change? – GOV.UK
Confirms UK offset changes between GMT and BST.
Document read:
The example illustrates the mechanism. Check current account conditions and instrument specifications with the provider.