Bid-Ask Spread in Forex

The bid-ask spread is the cost of executing a trade in forex. The bid is the price a dealer will pay to buy a currency; the ask is the price they will sell it. For EUR/USD, a tight spread might be 1–2 pips; a loose one might be 10–20 pips in volatile conditions. That gap is where liquidity providers—banks, brokers, market makers—extract their revenue. Understanding spreads is central to profitability, because no matter how accurately you predict price direction, a wide spread eats into returns.

Pips as the unit of measurement

In forex, a pip (percentage in point) is the smallest unit of movement quoted. For most major pairs, one pip is 0.0001. For USD/JPY and other yen pairs, it is 0.01. A spread is measured in pips: if the bid for EUR/USD is 1.0850 and the ask is 1.0852, the spread is 2 pips. You buy at 1.0852 and sell at 1.0850; the market must move 2 pips in your favour just for you to break even.

Why spreads exist: liquidity and risk

A market maker quotes both sides of the market—willing to buy and sell at posted prices. They absorb the risk that prices move against them between the time they buy and sell. For a highly liquid major pair like EUR/USD, that risk is tiny, so spreads are tight (often 0.1–0.5 pips in the interbank market). For a less liquid exotic pair like USD/ZAR (South African rand), the market maker faces higher risk of slippage, so spreads widen to 20–50 pips.

Spreads widen in volatility and low-liquidity windows

During normal market hours in major financial centres, spreads remain tight. But in the dead of night (Asia late evening, before Europe opens), or during geopolitical shocks, spreads blow out. Central bank announcements, interest-rate decisions, and employment data releases cause momentary volatility; bid and ask prices diverge as traders scramble to adjust. The spread can widen from 1 pip to 10–20 pips in seconds.

Fixed versus variable spreads

Retail forex brokers typically offer either fixed or variable spreads. A fixed spread (e.g., always 2 pips on EUR/USD) is predictable but often artificially wide; the broker charges a fixed fee embedded in the quote. A variable spread moves with market conditions—tight during liquid hours, wider at off-peak times. Variable spreads are often tighter on average but unpredictable, which can be dangerous if you’re scalping or running an algorithm that assumes a certain cost.

Markup on the interbank spread

Banks and ECNs quote tighter spreads to each other than retail brokers offer to clients. The interbank EUR/USD spread might be 0.1 pips; a retail broker quotes 1.5–2 pips. That difference is the broker’s profit, the cost of providing access, and a buffer for their own hedging and operational costs. High-frequency traders and institutional clients pay lower spreads because they trade large volumes and can afford to shop around; retail traders accept wider spreads.

How spreads affect profitability

For day traders and scalpers, spreads are decisive. If you scalp 100 pips of profit per trade but pay a 2-pip spread on entry and 2 pips on exit, you’ve given up 4% of returns before considering slippage, commissions, or adverse price movement. Spread traders (those betting on spreads narrowing) explicitly trade the gap: they sell at the ask in one pair and buy at the bid in another, capturing the reversion when spreads tighten.

Transparent pricing and ECNs

Electronic Communication Networks (ECNs) and STP brokers publish their spreads in real time, allowing traders to compare costs across providers. Some ECNs charge a small per-trade commission (e.g., 0.1% of the notional value) in exchange for tighter spreads—the all-in cost is lower if you’re trading in size. The choice between ECN (tighter spreads, commission) and market-maker (wider spreads, no commission) depends on your trade frequency and lot size.