Platform comparison
| Platform | YES odds | NO odds | Fee | KYC | Settlement | |
|---|---|---|---|---|---|---|
PolyGram Pick polygram.ink |
0% | 100% | 0% (USDC on-chain) | No-KYC up to $1,500 | USDC, auto via UMA oracle | Open on PolyGram → |
Polymarket polymarket.com |
0% | 100% | 0% | Geo-blocked in US/UK/EU | USDC, on-chain | Open on PolyGram → |
Kalshi kalshi.com |
— | — | Up to 7% per trade | US-only, KYC required | USD | Open on PolyGram → |
Betfair Exchange betfair.com |
— | — | 2-5% commission | Full KYC from first trade | GBP / EUR | Open on PolyGram → |
Manifold Markets manifold.markets |
— | — | Play-money (mana) | None — play-money | Mana (no cash-out) | Open on PolyGram → |
Live odds for Polymarket-based markets come from the Polygon order book. Non-Polymarket venues show attributes only; clicking any row opens the market on PolyGram.
Market context
This market will resolve to "Up" if the official S&P 500 Index open price for S&P 500 (SPX) on May 21 is higher than the official S&P 500 Index closing price for SPX on the most recent prior trading day. This market will resolve to "Down" if the official S&P 500 Index open price for S&P 500 (SPX) on May 21 is lower than the official S&P 500 Index closing price for SPX on the most recent prior trading day. E.g., ordinarily, a market on Monday would refer to the previous Friday for its most rece
Methodology
This page tracks S&P 500 (SPX) Opens Up or Down on May 21? across four political prediction venues. Live odds come from the Polymarket order book (the deepest political prediction-market book). Kalshi is the CFTC-regulated US alternative, Betfair the established UK sports-exchange with politics markets, Manifold the open play-money variant. PolyGram routes every trade through to Polymarket — at 0% fees.
Resolution & payout
For political markets the resolution source is decisive. Polymarket defines a concrete source per contract (e.g. AP, Reuters, official electoral commission) and uses the UMA Optimistic Oracle as the on-chain dispute mechanism. With a clearly defined outcome the USDC payout lands within minutes of the final confirmation.
FAQ
- Where can I trade this market with the lowest fees?
- On PolyGram, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.
- Is this market available outside the US?
- PolyGram is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.
- What's the difference between YES and NO shares?
- A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.
- What does it cost to trade on PolyGram?
- Zero. PolyGram routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.
- How reliable are the quoted odds?
- The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.
Trade S&P 500 (SPX) Opens Up or Down on May 21? on PolyGram
Live order book, 0% fees, USDC settlement in seconds.
Trade on PolyGram →