Execution-quality concept
Polymarket spread and executable price
Spread is the gap between the best bid and the best ask. It affects how different a visible or midpoint price can be from a practical executable price.
Best bid, best ask, and midpoint
The best bid is the strongest visible buy-side price. The best ask is the lowest visible sell-side price. The midpoint can summarize the market, but it is not necessarily a price that can be executed.
Why wide spread matters
A wide spread means the market has more execution friction. Entering from the ask side and exiting into the bid side can immediately expose a gap, even before considering deeper orderbook levels.
Spread is not a prediction signal
Spread says something about market mechanics and liquidity. It does not tell you which outcome will happen, and it should not be treated as trading advice.
Related concepts
Use the checker
Use RealityGap to compare spread, visible price, effective entry, slippage, and clean size.
Guardrail
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