Published on: 2026-08-13
Updated on: 2026-08-13
The London Fix is a major foreign exchange benchmark calculated around 4 PM London time. Large currency orders tied to that benchmark can arrive within the same short window, sometimes sending exchange rates sharply higher or lower without a major economic release. Knowing when the fix happens gives those sudden late-London moves more context.
The London Fix commonly refers to the WMR 4 PM Closing Spot Rates used for portfolio valuation, performance measurement and benchmark-linked transactions.
For major currencies, the fixing window runs from 3:57:30 PM to 4:02:30 PM London time.
Price pressure comes from an imbalance between buying and selling around the fix, rather than high volume alone.
Month-end, quarter-end and year-end fixes carry extra flow because portfolio currency hedges are rebalanced against them.
The London Fix commonly refers to the WMR 4 PM Closing Spot Rates, a set of foreign exchange benchmarks published at 4 PM London time. WMR closing rates were introduced in 1994 and became widely used for portfolio valuation, performance measurement and transactions linked to a common FX reference rate.
Foreign exchange trades throughout the working week, so there is no single universal closing price for currencies. A fund holding assets in several currencies still needs a consistent exchange rate to calculate what those holdings are worth in its reporting currency. The WMR rate provides that reference.
That common benchmark also explains why so much activity can gather around one point in the day.
Four PM is the centre of the WMR closing benchmark window.
London time |
What happens |
3:57:30 PM |
Fixing window begins |
4:00 PM |
Benchmark time |
4:02:30 PM |
Fixing window ends |
For major trade currencies, WMR samples actual transactions during those five minutes. If there are not enough valid trades, order-book prices can also be used. Median bid and offer rates are calculated separately to produce the benchmark rate.
The five-minute window has operated since February 2015. Before then, the main fixing period lasted only one minute. The Financial Stability Board recommended a wider window in 2014 as part of reforms designed to improve the integrity of major FX benchmarks.
The important time to remember is 4 PM London local time. The equivalent hour elsewhere changes when the UK switches between GMT and British Summer Time.
Banks, funds and other institutions execute large currency orders at the benchmark time.
For example, a fund needs to exchange several hundred million dollars into euros at a rate measured against that day’s WMR fix. Executing hours earlier could leave a large difference between its transaction price and the benchmark price, so the order may instead be executed close to the fixing window.
The same process can involve portfolio hedges, currency conversions and other benchmark-linked transactions. As those orders converge around 4 PM, the market has to absorb unusually concentrated demand.
Direction depends on the net order imbalance.
If €5 billion is bought while €4.9 billion is sold, there is heavy activity with a relatively small imbalance. If €5 billion needs to be bought while much less is offered for sale, prices may have to rise to attract enough sellers.
Selling pressure works the same way in reverse.
Some activity can also begin before 3:57:30 PM. Banks handling confirmed fixing orders may manage the market risk around those transactions before the official window opens, so fix-related price pressure does not have to begin exactly at 4 PM.
The last trading day of the month can bring extra fixing flow because changes in portfolio values can leave currency hedges too large or too small.
Suppose a portfolio begins the month with $1 billion of overseas assets and a matching currency hedge. If the assets rise to $1.1 billion, the hedge may need roughly another $100 million of adjustment to restore the original hedge ratio.
Similar adjustments across many portfolios can generate additional buying and selling around the month-end London Fix. Research on international equity hedging has found that these hedging trades can concentrate around the final 4 PM fix of the month.
Month-end does not guarantee a large move or reveal its direction. Buying and selling can offset each other, while economic news and unrelated flows can easily dominate the fix.
There is no dependable 4 PM reversal. Temporary order pressure may fade after the fixing window, allowing some of the move to retrace. Historical research found stronger reversal behaviour under the older market structure, while FCA research found short-term reversals around the fix had disappeared from its sample from 2015 onward.
A move supported by an interest-rate decision, economic surprise or another major catalyst can continue after 4 PM. The timing alone is therefore not a reason to trade against the move.
Open an intraday EUR/USD or GBP/USD chart and mark 4 PM London time. Then look at roughly the half hour on either side.
You may notice:
activity increasing shortly before the fixing window
a stronger directional move around 4 PM
price settling or retracing after the window
more obvious activity on some month-end sessions
Many days will show little unusual movement.
Timing also cannot prove that the fix caused a particular candle. Scheduled data, central-bank communication and other institutional flows can arrive around the same time. A sharp month-end move around 4 PM with no obvious scheduled catalyst is consistent with fixing flow, although the chart cannot confirm the cause by itself.
No. The WMR London Fix is a foreign exchange benchmark. The London gold benchmark operates separately in the bullion market with its own pricing process. The similar nickname does not mean the two benchmarks are connected.
The benchmark is centred on 4 PM London local time. Because the UK switches between GMT and British Summer Time, its equivalent time elsewhere changes during the year. Convert from London time rather than assuming a fixed local hour.
FTSE International Limited administers the WMR benchmarks within FTSE Russell, part of LSEG. The official WMR methodology determines how market data are collected, checked and used to produce the closing spot rates.
No. The fix tells you when benchmark-related order flow may become concentrated. It does not reveal whether buying or selling will dominate, how large the imbalance will be or whether another market catalyst will outweigh it.
The London Fix explains why forex can suddenly become active around 4 PM London time without a fresh economic headline. Large benchmark-linked orders can gather within a known five-minute window, and an imbalance between buyers and sellers can push exchange rates around. Knowing the timing gives you useful context, especially near month-end, while neither the fix nor a large 4 PM candle tells you where the currency must move next.
