Direct answer
An execution venue can affect both liquidity and spreads because it determines (1) where your order is routed, (2) which liquidity sources are eligible, and (3) how costs and risks are handled during execution. Even if the same currency pair is involved, different routing paths can lead to different effective bid/ask prices, especially when market conditions change.
Mechanism or definition
Liquidity is the availability of buyers and sellers at prices close to each other. Spreads are the difference between the quoted buy and sell prices (bid and ask). An execution venue can influence these through several stable mechanics:
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Routing and eligible liquidity: When orders are routed to different counterparties or pools, the venue decides which participants you interact with. If a venue routes to a pool that has deeper or more competitive quotes, the spread you observe can be tighter. If the routed pool is thinner, the spread can be wider.
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Market-to-market interaction speed: Some venues match orders faster to current quotes; others may introduce additional internal steps. When volatility rises, small delays can matter because quotes can move while the order is being processed.
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Cost handling and pricing model: The price you see as a spread may reflect different components, such as operational costs, risk controls, and how quickly quotes are updated. Two venues may show different spreads even with similar underlying market conditions because the “how” of execution differs.
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Order size and depth interaction: The venue’s ability to find counterparties for your order size can change the realized liquidity. If depth in the routed pool is limited, larger orders may have to access worse prices, widening the effective spread.
Assumption for examples below: we consider the same moment in time and the same currency pair, but allow the venue’s routing and liquidity pool characteristics to differ.
Evidence or example
Consider a simplified scenario with two venues, A and B.
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Venue A routes orders to a liquidity pool where many participants continuously quote around the current price. In calmer periods, bids and asks may be close, so the observed spread is often tighter because more quotes compete.
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Venue B routes to a pool with fewer active quotes or less willingness to trade at that time. Even if the mid-price is similar, fewer competitive quotes can make the bid/ask gap larger.
Now add a variable factor: volatility or participation changes. During fast market moves, some liquidity providers may reduce quoting or withdraw temporarily. If Venue A’s eligible liquidity also thins during those periods, the spread can widen there too. The key point is that the venue can change which liquidity is present for you to execute against at that time.
A second example focuses on costs that are not just the spread. Suppose one venue shows a slightly wider quoted spread but has lower other execution-related costs, while another venue shows a tighter spread but higher additional costs. Total trading cost can differ by venue even if liquidity conditions are otherwise similar.
Limitations and risks
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Liquidity can fail, not just “get worse”: In stress conditions, liquidity may disappear rather than merely widen. A wider spread can be a symptom of reduced participation, not a dependable measure of future outcomes.
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Observed spread depends on more than venue: Effective liquidity is affected by market conditions, order size, time-to-execution, and any additional charges. Historical patterns do not guarantee future behavior.
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Quotes are dynamic: Spreads and available depth can change quickly. Even with identical instructions, the realized outcome may differ across venues because the matching environment changes.
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Verification limitations: Without consistent definitions and comparable measurement, it is easy to confuse quoted spread with effective execution price (including slippage and other costs). Independent verification should compare how liquidity and effective costs behave across venues under the same stated assumptions.
Verification or next question
To verify the relationship between execution venue, liquidity, and spreads, define what you will measure before comparing venues:
- Which “spread”: quoted bid/ask spread versus effective spread (realized difference versus a reference mid-price). - Which time window and market regime: calm versus volatile periods, and whether you separate events where participation changes.