In this guide
Every transaction on PolyGram and Polymarket flows through a Central Limit Order Book — the identical matching infrastructure powering NASDAQ, NYSE, and all leading financial exchanges worldwide. Grasping CLOB fundamentals elevates your performance as a prediction market participant. Let's explore the mechanics.
What Is a Central Limit Order Book?
A Central Limit Order Book (CLOB) functions as a digital ledger capturing all unexecuted buy and sell orders for a given asset, organised by price level and temporal sequence. Upon arrival of a fresh order, the matching engine seeks to pair it with opposing orders already residing in the book.
Within prediction markets, the "asset" represents a YES or NO contract stake in a particular event. The CLOB for "Will Bitcoin surpass $100K in 2026?" displays every active order seeking YES contracts and every active order offering YES contracts (or equivalently, seeking NO contracts).
Reading the Order Book
- Bids (buy orders): Participants prepared to acquire YES contracts at a stated price or below. Arranged from highest to lowest price points.
- Asks (sell orders): Participants prepared to offload YES contracts at a stated price or above. Arranged from lowest to highest price points.
- Best bid: The uppermost price currently quoted by any prospective YES contract purchaser
- Best ask: The lowermost price currently quoted by any prospective YES contract seller
- Spread: The gap separating best ask from best bid. Narrow spread = robust market depth.
How Orders Match
Upon submission of a market order (acquire at prevailing rate), the CLOB engine:
- Identifies the current best ask (minimum seller quote)
- If your bid amount ≥ best ask: transaction settles at the ask amount
- Your order receives full or partial satisfaction contingent upon accessible depth
- Remaining unmatched quantity persists in the book as a fresh bid
Limit orders behave comparably yet only trigger when market conditions align with your preset threshold.
Why CLOB Matters for Traders
- Price improvement: Your transaction settles at the most favourable available rate, avoiding arbitrary surcharges
- Transparency: All unexecuted orders remain visible, informing your trading decisions
- No counterparty risk: The CLOB mechanism, rather than a designated intermediary, handles settlement
- Better prices vs AMM: CLOB-driven markets typically deliver narrower spreads relative to liquidity pools (AMMs)
CLOB vs AMM in Prediction Markets
Polymarket's CLOB (deployed by PolyGram) diverges fundamentally from liquidity-pool prediction markets such as earlier Augur iterations. CLOBs deliver precision pricing and substantial depth; liquidity pools ensure perpetual availability yet incur wider slippage on substantial orders. For the vast majority of prediction market scenarios, CLOB architecture proves advantageous.
FAQ
- What is slippage in a CLOB prediction market?
- Slippage materialises when your order magnitude surpasses obtainable depth at the optimal rate, forcing partial execution at less favourable rates. PolyGram computes and communicates projected slippage prior to trade confirmation.
- Can I place limit orders on PolyGram?
- Absolutely — you may designate a ceiling price for YES contracts or floor price for NO contracts. Your order persists within the CLOB until market conditions satisfy your threshold or you withdraw it.
- How often does the CLOB update?
- The Polymarket CLOB refreshes perpetually without interruption. PolyGram synchronises these changes with negligible delay through its CLOB connection layer.