In this guide
Trading activity across PolyGram and Polymarket flows through a Central Limit Order Book — the identical order-matching system employed by NASDAQ, NYSE, and all leading financial exchanges worldwide. Grasping how CLOB operates elevates your effectiveness as a prediction market participant. Let us walk through the mechanics.
What Is a Central Limit Order Book?
A Central Limit Order Book (CLOB) functions as a digital ledger capturing all active purchase and sale orders for a given asset, organised by price level and timestamp 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" refers to a YES or NO contract stake in a particular event. The CLOB for "Will Bitcoin exceed $100K in 2026?" displays every outstanding order to acquire YES contracts alongside every outstanding order to offload YES contracts (or equivalently, to acquire NO contracts).
Reading the Order Book
- Bids (buy orders): Participants prepared to acquire YES contracts at a stated price point or less. Arranged from highest price downward.
- Asks (sell orders): Participants prepared to offload YES contracts at a stated price point or more. Arranged from lowest price upward.
- Best bid: The uppermost price level at which a buyer currently stands ready to purchase YES contracts
- Best ask: The lowermost price level at which a seller currently stands ready to sell YES contracts
- Spread: The gap separating best ask from best bid. Narrow spread indicates robust market depth.
How Orders Match
Upon submission of a market order (acquire at prevailing rates), the CLOB matching system:
- Identifies the prevailing best ask (minimum seller price)
- Should your bid amount ≥ best ask: execution occurs at the ask price
- Your order satisfies in full or in part contingent upon accessible volume
- Remaining unexecuted portions lodge in the book as a fresh bid
Limit orders behave in parallel fashion but trigger only when market conditions attain your designated threshold.
Why CLOB Matters for Traders
- Price improvement: Your order settles at the most advantageous obtainable rate, absent any preset surcharge
- Transparency: Every pending order sits visible, enabling informed trading judgements
- No counterparty risk: The CLOB engine, rather than a human intermediary, handles your transaction
- Better prices vs AMM: CLOB-driven markets typically deliver narrower spreads relative to automated market makers (AMMs)
CLOB vs AMM in Prediction Markets
Polymarket's CLOB (powering PolyGram) diverges fundamentally from AMM-based prediction markets such as earlier iterations of Augur. CLOBs furnish granular pricing and order-book depth; AMMs guarantee perpetual liquidity availability yet incur wider slippage on sizable transactions. In the majority of prediction market scenarios, CLOB architecture proves advantageous. For a thorough comparison of available systems, consult our guide.
FAQ
- What is slippage in a CLOB prediction market?
- Slippage materialises when your order volume surpasses liquidity accessible at the optimal price tier, forcing portions of your order to settle at less favourable rates. PolyGram calculates and displays projected slippage prior to order confirmation.
- Can I place limit orders on PolyGram?
- Absolutely — you may designate an upper threshold for YES contract acquisition or a floor for NO contract acquisition. Your order persists within the CLOB until market conditions satisfy your price requirement or you withdraw it.
- How often does the CLOB update?
- The Polymarket CLOB refreshes perpetually without interruption. PolyGram synchronises these refreshes instantaneously through its CLOB connection infrastructure.