In this guide
Key takeaway: Liquidity stands as the cornerstone of successful prediction market trading. When liquidity runs deep, traders enjoy compressed bid-ask spreads, rapid order execution, and market prices that accurately reflect true probabilities. Polymarket dominates the space with $1.5B+ in total traded volume; rival platforms typically command substantially lower activity levels.
Prediction market liquidity shapes your entire trading experience — influencing both the cost basis of your entry and the speed at which you can unwind exposure. Yet many newcomers prioritise market selection over liquidity assessment. This guide demonstrates why liquidity fundamentals outweigh all other considerations.
What is liquidity?
Within financial markets, liquidity describes the ease with which you can transact an asset without materially shifting its quoted price. Prediction markets express liquidity across three distinct dimensions:
- Depth: The aggregate quantity of shares resting at successive price tiers within the order book
- Spread: The separation between the highest bid level (maximum purchase price) and lowest ask level (minimum sale price)
- Volume: The total quantity of shares exchanged throughout a specified timeframe
A market displaying 10,000 shares bidding at 48 cents and 10,000 offered at 50 cents exhibits strong liquidity. Conversely, a market with merely 50 shares on either side separated by a 10-cent gap demonstrates poor liquidity.
Why liquidity matters for traders
Insufficient liquidity erodes your returns through multiple channels:
- Wider spreads: Transaction costs increase both when establishing and closing positions
- Slippage: Sizeable trades push market prices unfavourably against your direction
- Trapped positions: Absence of willing counterparties may prevent you from liquidating holdings before market settlement
- Price inaccuracy: Sparse trading activity prevents prices from converging toward genuine outcome probabilities
How to measure prediction market liquidity
Prior to executing any trade, evaluate these key metrics:
- Order book depth: On PolyGram, leverage the depth chart to examine the architecture of buy and sell interest
- 24h volume: Elevated trading activity correlates with improved order fill probability — especially for standard position sizes
- Number of unique traders: Markets attracting 100+ distinct participants typically offer sufficient liquidity for standard retail allocations
- Spread percentage: Target markets where the bid-ask gap remains beneath 3 cents (3%) to minimise transaction friction
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 simultaneously post competing bids and offers, capturing the spread differential whilst furnishing trading counterparties with immediate execution. Polymarket compensates these participants through fee concessions and MATIC token incentives. PolyGram's proprietary liquidity engine replicates Polymarket's order flow, guaranteeing PolyGram participants access to equivalent market depth as those trading directly on Polymarket.
Tips for trading illiquid markets
- Deploy limit orders exclusively — avoid market orders when order book depth is minimal
- Distribute substantial orders across multiple price points to minimise market impact
- Exercise patience: place your desired price and allow the market to fill your order rather than accepting unfavourable terms
- Assess the settlement timeline — markets frequently experience liquidity expansion as resolution approaches
Trade on the most liquid prediction market platform. Start trading on PolyGram →