Most prediction-market screeners rank by volume. Volume tells you what already happened; liquidity tells you what you can do now. These are the 30 Polymarket markets with the deepest standing order books — the markets where you can place a $1K position and barely move the mid.
Top 30 Markets by Liquidity
| # | Market | Category | Liquidity | Volume |
|---|---|---|---|---|
| #1 | US x Iran ceasefire by April 7? | politics | $20.0M | $173.3M |
| #2 | Russia x Ukraine ceasefire by May 31, 2026? | politics | $15.5M | $126.7M |
| #3 | Netanyahu out by March 31? | politics | $14.7M | $104.2M |
| #4 | US forces enter Iran by March 31? | geopolitics | $13.8M | $73.9M |
| #5 | Will the Fed decrease interest rates by 50+ bps after the April 2026 meeting? | economics | $12.8M | $62.9M |
| #6 | Will "Donk" be said during the PGL Bucharest 2026 Grand Final? | other | $12.5M | $5.6M |
| #7 | Military action against Iran ends by April 17, 2026? | geopolitics | $8.7M | $28.7M |
| #8 | Will the Fed decrease interest rates by 50+ bps after the March 2026 meeting? | economics | $7.7M | $173.2M |
| #9 | Russia x Ukraine ceasefire by June 30, 2026? | politics | $7.3M | $56.0M |
| #10 | Will Iraq win the 2026 FIFA World Cup? | sports | $7.1M | $11.2M |
| #11 | Will Panama win the 2026 FIFA World Cup? | sports | $7.0M | $11.3M |
| #12 | Will Qatar win the 2026 FIFA World Cup? | sports | $6.9M | $22.8M |
| #13 | Will Bosnia-Herzegovina win the 2026 FIFA World Cup? | sports | $6.9M | $9.5M |
| #14 | US forces enter Iran by April 30? | geopolitics | $6.9M | $267.6M |
| #15 | Will Tunisia win the 2026 FIFA World Cup? | sports | $6.8M | $20.3M |
| #16 | Will Haiti win the 2026 FIFA World Cup? | sports | $6.8M | $16.7M |
| #17 | Will Jordan win the 2026 FIFA World Cup? | sports | $6.7M | $24.3M |
| #18 | Will Israel launch a major ground offensive in Lebanon by March 31? | geopolitics | $6.6M | $74.6M |
| #19 | QatarEnergy announces/resumes LNG production in Qatar by April 30? | other | $6.6M | $25.4M |
| #20 | Will Cape Verde win the 2026 FIFA World Cup? | sports | $6.6M | $21.1M |
| #21 | Will Ghana win the 2026 FIFA World Cup? | sports | $6.5M | $16.6M |
| #22 | Will Algeria win the 2026 FIFA World Cup? | sports | $6.5M | $20.1M |
| #23 | Will South Africa win the 2026 FIFA World Cup? | sports | $6.5M | $25.4M |
| #24 | Will Saudi Arabia win the 2026 FIFA World Cup? | sports | $6.5M | $25.6M |
| #25 | Will Ivory Coast win the 2026 FIFA World Cup? | sports | $6.5M | $19.6M |
| #26 | Will Curaçao win the 2026 FIFA World Cup? | sports | $6.4M | $34.1M |
| #27 | Will there be no change in Fed interest rates after the March 2026 meeting? | economics | $6.3M | $85.4M |
| #28 | Will Canada win the 2026 FIFA World Cup? | sports | $6.2M | $21.4M |
| #29 | Will New Zealand win the 2026 FIFA World Cup? | sports | $6.0M | $29.0M |
| #30 | Will Egypt win the 2026 FIFA World Cup? | sports | $5.9M | $21.7M |
Liquidity = sum of resting orders within 5¢ of mid on both sides. Captured 2026-05-16 from the Protodex dataset.
Volume / Liquidity Ratio — A Cleaner Signal
A high volume-to-liquidity ratio means the market is being traded faster than market makers can replenish — a sign of fresh information. A low ratio means the order book is full but no one's hitting it — typical of stale or boring markets. The full dataset (with 15-minute orderbook snapshots) lets you watch this ratio over time. Get the dataset →
Practical Takeaway
- Sizing rule: Position size ≤ 5% of one-sided liquidity, or you eat 1-3¢ of slippage on entry and exit. On a 50¢ market that's a 4-6% drag — fatal for most edges.
- Bid-ask spread floor: Anything above 3¢ wide is paying market makers' rent, not capturing edge.
- Liquidity decay: Markets bleed liquidity as resolution approaches. The widest spreads are usually 1-3 days from settlement.
📊 The Full Polymarket Historical Dataset
10.8M+ price snapshots across 13,900+ prediction markets. 15-minute frequency, orderbook depth, 43+ days of data. Use the same source data behind this post for your own backtests, models, and research.
Get the dataset →