In this guide
Every trade executed on PolyGram and Polymarket flows through a Central Limit Order Book — the identical matching infrastructure deployed by NASDAQ, NYSE, and all major financial exchanges worldwide. Grasping how CLOB functions will sharpen your approach as a prediction market participant. Let's explore the mechanics.
What Is a Central Limit Order Book?
A Central Limit Order Book (CLOB) is a digital ledger capturing all unexecuted buy and sell orders for a given asset, organised by price level and submission sequence. When a fresh order enters the system, the matching engine seeks to pair it with existing orders on the opposing side of the ledger.
Within prediction markets, the "asset" refers to a YES or NO contract tied to a particular outcome. The CLOB for "Will Bitcoin exceed $100K in 2026?" displays every active order seeking to acquire YES contracts and every active order offering to sell YES contracts (or equivalently, to acquire NO contracts).
Reading the Order Book
- Bids (buy orders): Participants prepared to acquire YES contracts at a designated price threshold or below. Displayed from greatest to least.
- Asks (sell orders): Participants prepared to dispose of YES contracts at a designated price threshold or above. Displayed from least to greatest.
- Best bid: The uppermost price at which a buyer currently stands ready to purchase YES contracts
- Best ask: The lowermost price at which a seller currently stands ready to sell YES contracts
- Spread: The gap separating best ask from best bid. Narrow spread = robust market depth.
How Orders Match
Upon submitting a market order (acquire at prevailing rate), the CLOB engine:
- Identifies the present best ask (minimum seller rate)
- If your bid amount ≥ best ask: transaction settles at the ask rate
- Your order gets satisfied wholly or in part contingent on obtainable depth
- Unmatched remainder stays in the ledger as a fresh bid
Limit orders behave comparably but trigger only when the market arrives at your chosen threshold.
Why CLOB Matters for Traders
- Price improvement: Your order settles at the most favourable accessible rate, avoiding fixed surcharges
- Transparency: All unexecuted orders remain visible, informing your trading choices
- No counterparty risk: The CLOB engine, rather than an individual intermediary, handles your transaction
- Better prices vs AMM: CLOB-driven markets typically deliver narrower spreads relative to algorithmic market makers (AMMs)
CLOB vs AMM in Prediction Markets
Polymarket's CLOB (leveraged by PolyGram) diverges from AMM-based prediction markets such as earlier iterations of Augur. CLOBs furnish granular pricing and substantial order depth; AMMs guarantee perpetual liquidity availability yet incur broader slippage on substantial trades. In the majority of prediction market scenarios, CLOB architecture proves advantageous.
FAQ
- What is slippage in a CLOB prediction market?
- Slippage materialises when your order surpasses the obtainable depth at the optimal rate, forcing portions of your order to settle at less desirable rates. PolyGram furnishes projected slippage estimates prior to finalising any transaction.
- Can I place limit orders on PolyGram?
- Absolutely — you may establish an upper threshold for YES contract acquisition or lower threshold for NO contract acquisition. Your order persists in the CLOB until the market achieves your threshold or you withdraw it.
- How often does the CLOB update?
- The Polymarket CLOB refreshes perpetually without interruption. PolyGram mirrors these refreshes with negligible delay through its CLOB connection.