In this guide
Key takeaway: Liquidity stands as the paramount consideration for prediction market participants. Robust liquidity delivers compressed spreads, instantaneous execution, and reliable price discovery. Polymarket dominates with $1.5B+ in cumulative volume; alternative venues typically provide substantially less depth.
Prediction market liquidity shapes your entire trading environment — from execution costs to position exit velocity. Yet novice traders frequently prioritise market selection over liquidity assessment. This resource examines why liquidity supersedes all other considerations.
What is liquidity?
Within financial markets, liquidity reflects the ease with which you can acquire or dispose of an asset whilst maintaining price stability. For prediction markets, liquidity comprises three distinct elements:
- Depth: Share availability across successive price tiers within the order book
- Spread: The differential between peak bid (maximum purchase price) and peak ask (minimum sale price)
- Volume: Total share transactions executed during a specified timeframe
A market displaying 10,000 shares at 48 cents on the buy side and 10,000 on the sell side at 50 cents demonstrates adequate liquidity. Conversely, 50 shares on each side with a 10-cent separation signals poor liquidity.
Why liquidity matters for traders
Insufficient liquidity erodes your returns through multiple channels:
- Wider spreads: Entry and exit costs increase substantially
- Slippage: Sizeable trades push prices unfavourably
- Trapped positions: Absence of buyers prevents pre-resolution exits
- Price inaccuracy: Sparse trading prevents accurate probability representation
How to measure prediction market liquidity
Prior to executing trades, evaluate these metrics:
- Order book depth: PolyGram's depth chart displays buy and sell concentration visually
- 24h volume: Elevated trading activity facilitates faster order completion
- Number of unique traders: Markets hosting 100+ distinct participants typically accommodate retail positions adequately
- Spread percentage: Target markets maintaining spreads below 3 cents (3%) for economical execution
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 complementary buy and sell orders, earning the spread whilst supplying depth to the broader trading community. Polymarket incentivises these participants through fee reductions and MATIC compensation. PolyGram's proprietary liquidity engine replicates Polymarket's order book architecture, guaranteeing PolyGram participants access to equivalent depth as native Polymarket traders.
Tips for trading illiquid markets
- Deploy limit orders exclusively — avoid market orders in thin conditions
- Fragment sizeable orders across multiple price points
- Exercise patience: establish your target price and await execution rather than accepting unfavourable fills
- Account for temporal dynamics — thin markets frequently deepen approaching settlement
Trade on the most liquid prediction market platform. Start trading on PolyGram →