How Polymarket works, what whale traders are, how to read YES/NO odds, the math behind probability markets, and how every poly-sim.com tool helps you see what the crowd is pricing in.
A prediction market is a financial exchange where participants trade contracts whose payoff depends on the outcome of a future event. The price of a contract at any moment reflects the collective probability estimate of that outcome — pooling the information and beliefs of every participant.
If a contract trades at 72¢, the market collectively believes there is a 72% probability the event will occur. When the event resolves, YES contracts pay $1.00 and NO contracts pay $0.00 (or vice versa).
Yes — consistently, across multiple domains. Studies from Science journal and Tetlock's Good Judgment Project show that well-structured prediction markets outperform:
The reason: participants have skin in the game. Money aligns incentives to be accurate, not merely opinionated. Want to dig deeper? Read our full guide to prediction markets.
Almost any verifiable, time-bound event. On Polymarket you'll find markets covering:
You can explore all active markets on our Poly-Sim Score — 500+ markets rated and searchable.
Polymarket is the world's largest decentralized prediction market platform. It operates on the Polygon blockchain, allowing anyone globally (outside the US) to trade on real-world event outcomes. Collateral is held in pUSD (Polymarket USD) — a 1:1 USDC-backed token settled in native USDC.
Polymarket uses a Central Limit Order Book (CLOB) model — the same mechanism used by professional financial exchanges. Prices are determined by real buy and sell orders, not by an algorithm. This makes Polymarket's prices more reliable than simpler AMM-based prediction markets.
pUSD (Polymarket USD) is Polymarket's native collateral token on the Polygon blockchain. It is a standard ERC-20 token backed 1:1 by USDC, with the backing enforced onchain by Polymarket's smart contract — no algorithmic peg, no fractional reserve.
Polymarket migrated from USDC.e (a bridged form of USDC) to pUSD in 2025 for better capital efficiency and settlement reliability. All trading activity settles in native USDC. For traders, the experience is identical — you deposit, see a dollar balance, trade, and withdraw.
Read the full breakdown: What Is pUSD? Polymarket's New Collateral Token Explained →
pUSD's 1:1 backing is enforced onchain by code — not by Polymarket's balance sheet or a market mechanism. This means:
Polymarket automatically migrated all USDC.e balances to pUSD. The dollar value is identical. No action was required from traders — existing balances were converted transparently.
If you've been away from Polymarket for a while and notice your balance shows pUSD instead of USDC.e, this is why. Your funds are intact.
Potentially. The USDC.e → pUSD migration may constitute a token swap event in some jurisdictions, which could be a taxable disposal. In practice, because both tokens are 1:1 USD-pegged with zero gain/loss, the tax impact is likely nil in most cases — but you should document it.
For Polymarket traders with significant activity, we recommend using a crypto tax tool to track all token events. See our Crypto Tax Guide and Tax Estimator Calculator.
Each market has a defined resolution source established at creation — usually a credible data provider, official announcement, or verifiable news source. When the resolution date passes:
$1.00 USDC per share if YES wins$0.00 if YES wins (and vice versa)Learn the full mechanics in our How Polymarket Works guide.
No. Polymarket is geo-blocked for US residents due to CFTC regulations on prediction markets as commodity derivatives. It is accessible globally in most other jurisdictions.
YES and NO prices are expressed in US cents (¢) and represent probability percentages:
YES 72¢ = the market assigns a 72% probability the event happensNO 28¢ = the market assigns a 28% probability it doesn't happen$1.00 (with a small spread)Our Probability & Odds guide explains how to convert YES% into implied probability and compute your edge.
The 24-hour price change shows how much a market's YES probability has moved in the last day. A +8.5% move means the market now prices the event 8.5 percentage points more likely than 24 hours ago — significant new information has likely entered the market.
Our Ripple Effect tool uses these 24h moves to identify "causal chains" — markets where one event is leading a narrative shift and related markets haven't caught up yet. This is where pricing gaps (and opportunities for informed analysis) emerge.
The bid-ask spread is the difference between the highest price a buyer will pay (bid) and the lowest price a seller will accept (ask). On Polymarket's binary markets, typical spreads are 2–6 cents on liquid markets, widening to 10–20 cents on thin markets.
A narrow spread indicates high liquidity and reliable pricing. A wide spread means fewer participants and higher execution cost. Our BTC Strategy Simulator accounts for realistic bid-ask spread and slippage in all its performance calculations.
In crypto and prediction markets, a whale is a trader whose positions are large enough to signal strong conviction — and sometimes move markets. On poly-sim.com, we track trades above $1,000 USD by default, with filters for $5k+, $10k+, $25k+, and $50k+.
The largest Polymarket whales regularly open single positions of $50,000–$1,000,000+. These are often well-researched trades by sophisticated participants who believe they have an informational edge.
Whale activity is a signal, not a guarantee. Large traders have superior information or analysis in many cases — but they also lose big regularly. Reasons to be cautious:
The best use of whale data is as a filter — one input among several, not a trade trigger. Read our Whale Trading Psychology guide for a deeper analysis.
Yes. Polymarket uses Polygon blockchain addresses (e.g. 0x1a2b…f9a0). Wallets are pseudonymous — all trades are publicly visible on-chain, but wallet controllers are not identified unless they publicly reveal themselves.
Our Hall of Whales leaderboard ranks the top wallets by Combo Score (volume × position size × win rate) and our Wallet Tracker lets you deep-dive any specific address.
PnL = Profit and Loss. It's the net gain or loss from all closed (resolved) positions. A wallet showing PnL: +$14,200 has made $14,200 in net profit across all resolved markets.
Track any wallet's full PnL breakdown with our Wallet Tracker.
Win rate is the percentage of resolved positions where the trader ended on the winning side. A win rate of 73% means correct on 73 out of 100 resolved markets.
However, win rate alone is misleading. A trader who bets very small amounts on 90% favorites will have a high win rate but poor returns. The key metric is calibrated edge — how often you're right given the probability you paid.
The Kelly Criterion is a mathematical formula for optimal bet sizing that maximizes long-run bankroll growth. For prediction markets:
Kelly % = (edge) / (odds at risk)
Where edge = your estimated probability − market price. If you believe an event is 75% likely but the market prices it at 60%, your edge is 15 percentage points.
Full Kelly is aggressive — most sophisticated traders use half-Kelly or quarter-Kelly to reduce variance. Read the full math and use the interactive simulator in our Bankroll Management guide.
Several evidence-based approaches are used by successful prediction market traders:
Read our comprehensive Prediction Market Strategies guide for a full breakdown of each approach with examples.
Narrative ripple trading exploits the fact that related prediction markets often reprice sequentially, not simultaneously. When major new information enters the market, a primary "leader" market moves quickly — but correlated "echo" markets lag behind, sometimes by hours.
This lag creates a window where an informed observer can identify which echo markets haven't yet incorporated the information. Our Ripple Effect tool uses AI causal chain analysis and PropScore (0–100) to identify and rank these gaps automatically. This is simulation and educational — not a trading signal.
Polymarket's BTC 5-minute binary markets are highly efficient — but our BTC Strategy Simulator tests 60+ algorithms including Mean Reversion, Momentum, Scalp, and Hedge strategies live against real market prices.
Performance varies by market regime. Mean Reversion strategies tend to outperform in range-bound markets; Momentum strategies outperform during trending cycles. The simulator shows live win rates and PnL for all strategies simultaneously — so you can identify which approach fits the current conditions. Simulation only — not real trading.
poly-sim.com is a free suite of Polymarket intelligence tools. All tools are free, require no account, and read public Polymarket API data:
Our Cloudflare Worker polls the Polymarket CLOB and Gamma APIs every few minutes for large trades. Trades are filtered by minimum size threshold ($1k–$50k+ configurable) and ranked by size and time. Results are cached in Cloudflare KV to minimize API load.
PropScore (0–100) is a composite signal strength metric for echo market opportunities. It combines four factors:
Only echoes with PropScore ≥ 45 are shown. This filters out noise and surfaces only structurally meaningful correlations.
All data comes directly from Polymarket's public APIs:
We do not modify or fabricate data. All figures reflect real Polymarket market prices and volumes. Our Cloudflare Worker aggregates and caches this data with typical freshness of 2–15 minutes depending on the tool.
No. poly-sim.com is an independent analytics and education platform. We are not affiliated with, endorsed by, or connected to Polymarket Inc. in any way. We use Polymarket's public API under their standard terms.