Key takeaway: Liquidity stands as the paramount consideration for anyone trading prediction markets. When liquidity runs deep, you benefit from compressed bid-ask spreads, rapid order execution, and market prices that reflect genuine probabilities. Polymarket dominates the space with over $1.5B in total traded volume; rival platforms typically lag considerably behind in available depth.
Prediction market liquidity shapes your entire trading experience — affecting both the cost of entry and your ability to unwind positions swiftly. Yet newcomers often prioritise market selection over liquidity assessment. This article clarifies why liquidity supersedes all other considerations.
What is liquidity?
Liquidity in financial markets refers to the capacity to transact an asset in volume without materially affecting its price. Within prediction markets, three distinct dimensions define liquidity:
- Depth: The quantity of shares available at various price tiers throughout the order book
- Spread: The differential between the highest purchase offer and the lowest sale price
- Volume: The aggregate number of shares traded during a specified timeframe
A market offering 10,000 shares at 48 cents on the buy side and 10,000 at 50 cents on the sell side demonstrates strong liquidity. Conversely, 50 shares per side with a 10-cent gap indicates poor liquidity.
Why liquidity matters for traders
Insufficient liquidity erodes your returns through multiple channels:
- Wider spreads: Your entry and exit costs increase substantially
- Slippage: Sizable positions push prices unfavourably during execution
- Locked capital: Absent buyer interest leaves you unable to liquidate before market settlement
- Mispriced outcomes: Thin markets fail to accurately capture real-world probabilities
How to measure prediction market liquidity
Evaluate these metrics prior to committing capital:
- Order book depth: Leverage PolyGram's depth chart to examine bid and ask concentrations
- 24h volume: Elevated trading activity signals easier order fills
- Number of unique traders: Markets attracting 100+ distinct participants typically possess sufficient liquidity for standard retail positions
- Spread percentage: Target markets where spreads remain below 3 cents (3%) for economical entry and exit
Which platforms have the most liquidity?
| Platform | Cumulative volume | Avg. spread |
| Polymarket | $1.5B+ | 1-3 cents |
| Kalshi | $500M+ | 2-5 cents |
| Betfair Exchange | N/A (sports-focused) | 1-2% on sports |
| Augur/Azuro | $50M+ | 5-15 cents |
How market makers create liquidity
Institutional liquidity providers deploy matched buy and sell orders simultaneously, capturing the spread whilst supplying depth to the broader market. Polymarket compensates these market makers through fee reductions and MATIC incentives. PolyGram's proprietary liquidity engine replicates Polymarket's order book structure, guaranteeing PolyGram participants access to identical depth as those trading directly on Polymarket.
Tips for trading illiquid markets
- Employ limit orders only — avoid market orders when trading thin order books
- Divide substantial positions across multiple price points
- Exercise patience: place your bid and await execution rather than accepting unfavourable prices
- Assess timing dynamics — liquidity often strengthens as markets approach resolution
Trade on the most liquid prediction market platform. Start trading on PolyGram →