London session

The London session runs 08:00 to 17:00 London time, and its reputation as the busiest window is not folklore. It is measured. ### It genuinely is the biggest venue The [BIS Triennial Central Bank Survey](https://www.bis.org/statistics/rpfx25_fx.htm) for April 2025 found global OTC foreign exchange turnover of $9.6 trillion per day, and that roughly **38% of it was booked in the United Kingdom**, against about 19% in the United States. London is not simply an active session. It is the single largest FX dealing location in the world, and it has held that spot survey after survey. That concentration is what you actually feel on the chart. More desks awake means more resting orders, more counterparties, and tighter quotes. Depth is not a mood, it is a headcount. It also explains the pair bias. The same BIS survey puts the euro on one side of 28.9% of all trades and sterling on 10.2%. When European bank desks, corporate treasuries and asset managers act on their own currencies, they act in this window. ### The shape of the session Asia usually hands over a relatively contained range. London arrives with the day's first serious order flow and resolves it. That is the mechanical reason this session has a reputation for producing the day's real directional move rather than chop. ### The 4pm fix is a real thing on your chart LSEG publishes the [WM/Refinitiv closing spot rate](https://www.lseg.com/en/ftse-russell/benchmarks/wmr-fx-benchmarks) every weekday at **4:00 pm London time**, and it was designated a Critical Benchmark under UK Benchmark Regulation in November 2024. Index funds, pension hedges and month-end rebalancing are all executed against that print. So a sharp, seemingly unprovoked move late in the London session is sometimes just someone filling a benchmark order. It is flow, not a signal, and it does not care about your setup. ### Where beginners get hurt The classic error is treating the first break of the Asian range as *the* move. The hour around the open is when liquidity gets probed, and a first push through an overnight high or low can fail before real direction sets in. "Busiest" does not mean "most forgiving." It means the most participants, moving fastest, including the ones who can see exactly where the stops are stacked.