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Prediction Market Liquidity: Why It Matters and How to Find Deep Markets

Liquidity determines your execution quality in prediction markets. Learn how to read depth, identify liquid markets, and avoid the pitfalls of illiquid order books.

Sarah Whitfield
Markets Editor — Political Forecasting · 1 May 2026 · 3 min read

Market liquidity stands as the paramount consideration determining your ability to execute trades at reasonable prices within prediction markets. Markets with strong liquidity enable you to open and close positions at competitive rates; conversely, thin markets impose substantial costs through wide spreads before any outcome materialises.

What Is Liquidity in Prediction Markets?

Liquidity describes the ease with which you can transact shares whilst maintaining stable pricing. A prediction market demonstrating robust liquidity exhibits:

  • Narrow bid-ask spread (distance between highest buy and lowest sell offers remains minimal)
  • Substantial order book depth (numerous orders distributed across price tiers)
  • Elevated recent transaction activity
  • Broad participation from traders seeking both outcomes

Signs of a Liquid Market

  • Spread under 2 cents: A YES contract quoted at 0.65 bid / 0.67 ask represents a 2-cent spread — exceptionally narrow by prediction market standards
  • Large open interest: Substantial dollar amounts in circulating YES and NO contracts
  • Recent trades: Most recent transaction occurring within minutes rather than extended periods
  • Volume over $10,000: Markets displaying considerable daily turnover typically accommodate standard trading sizes without difficulty

Impact on Your Trading

When entering a market exhibiting a 5-cent spread, you incur an immediate 5-cent-per-share penalty upon entry — independent of subsequent price fluctuations. By contrast, a 1-cent spread market reduces this friction by approximately 80%. Across numerous transactions, such differences accumulate substantially.

Illustration: Acquiring 1,000 YES shares across markets with differing spreads:

  • 5-cent spread: upfront expense $50 (spread-related only)
  • 1-cent spread: upfront expense $10
  • Monthly trading across 20 markets annually: $960 versus $192

Where to Find the Most Liquid Prediction Markets

PolyGram's deepest liquidity concentrates in these categories:

  1. Prominent American political contracts (electoral outcomes, legislative majorities)
  2. Cryptocurrency benchmarks for Bitcoin and Ethereum valuations
  3. American sporting championships including Super Bowl and NBA Finals (in-season)
  4. Central bank policy determination markets, particularly interest rate announcements
  5. International football tournaments such as World Cup championship predictions (tournament period)

Sort by transaction volume at PolyGram markets — arranging by Volume reveals highest-liquidity contracts at the top.

FAQ

Can I trade illiquid markets safely?
Certainly, provided you exercise appropriate caution. Employ limit orders to establish your entry price rather than accepting market rates. Refrain from accumulating positions unless you can exit them profitably despite the prevailing spread.
How does liquidity change over a market's life?
Typically, newly-created markets experience sparse trading initially, with participation intensifying as the event approaches and trader attention increases. The period immediately preceding major event resolution frequently witnesses peak liquidity levels.
Does PolyGram have the same liquidity as Polymarket?
PolyGram connects directly to Polymarket's CLOB infrastructure, ensuring equivalent liquidity availability and order book composition.
Sarah Whitfield
Markets Editor — Political Forecasting

Sarah has tracked political prediction markets and election forecasting since the 2020 US cycle. Focus: US presidential, congressional, and UK parliamentary contracts.