In plain English
What Session overlap means
Because forex activity moves across global time zones, the boundaries of regional sessions can coincide. During an overlap, more banks, dealers, funds, and electronic venues may be active than during a quieter period. This can increase available liquidity for some pairs, but the extent varies by currency, day, event calendar, and trading venue.
Why it matters
Session overlap is often used as a practical timing reference because market conditions may differ when multiple major centers are open. More activity may support tighter quoted spreads or greater market depth, but neither outcome is assured. High-impact news can instead produce fast price changes, gaps in available liquidity, and slippage.
Example
During a London–New York overlap, a trader places a market order in EUR/USD just as U.S. inflation data are released. Although both regional centers are active, the order can still fill at a worse price than expected if prices move before execution. More participants do not eliminate event-driven execution risk.
Quick answers
Common questions
What is the main forex session overlap?+
The London–New York overlap is the most commonly referenced one because it joins two major FX centers. Its exact displayed hours depend on the chosen time zone and on seasonal daylight-saving changes.
Does session overlap always mean lower spreads?+
No. Greater concurrent activity can improve liquidity, but spreads remain variable. They can widen because of economic releases, holidays, volatile markets, a broker’s pricing model, or reduced liquidity in a particular currency pair.
Sources