# Trading Overview
Trading on Probly runs on a **Central Limit Order Book (CLOB)** — the same model used by traditional exchanges. Every order is matched transparently against a public, user-to-user order book.
## How Shares Work
Each market has two outcome shares — **YES** and **NO** — priced between **1¢ and 99¢**.
* Price = the market's implied probability (60¢ ⇒ 60% chance)
* 1 YES + 1 NO is always collateralized by **$1.00** USDC
* At resolution, the winning side redeems for **$1.00** and the losing side for **$0**
For a deeper walkthrough, see [What is Probly?](/get-started/readme.md#how-a-share-works).
## The Order Book
Each market has its own book, split into **Bids** (buy orders, on the left) and **Asks** (sell orders, on the right). The current **last trade** and **spread** sit just below the two sides.
Both sides put their **best price at the top row**: the highest bid on the left, the lowest ask on the right. The further down each side you go, the worse the price gets.
| Column | Meaning |
| ---------- | -------------------------------------------------------------------- |
| **Price** | Price per share, in ¢ (1 – 99) |
| **Shares** | Shares resting at that price |
| **Total** | Price × Shares ÷ 100, in USDC |
| **Last** | The most recent executed trade |
| **Spread** | Lowest Ask − Highest Bid. A tighter spread means lower cost to trade |
Switch between YES and NO by clicking the other outcome card — the layout is identical.
## Order Types
| Type | How it works |
| ----------------------------------------------------- | ----------------------------------------------------------------- |
| [Market Order](/markets-and-trading/market-orders.md) | Executes immediately against the best available resting orders |
| [Limit Order](/markets-and-trading/limit-orders.md) | Rests on the book at your chosen price until matched or cancelled |
## Buying YES vs NO
Buying YES and buying NO are **symmetric**:
* Price(YES) + Price(NO) ≈ $1.00 at all times
* Buying YES at **60¢** is equivalent to betting against NO at **40¢**
Use whichever side has better liquidity or is easier to reason about.
## Minimums & Precision
| Rule | Value |
| ------------------ | ---------------------------------- |
| Minimum order size | **5 shares** |
| Price range | **1¢ – 99¢** |
| Share precision | Up to 2 decimal places (e.g. 5.25) |
Orders below the minimum are rejected by the exchange.
## Where to Next
* [Market Orders](/markets-and-trading/market-orders.md) — instant execution
* [Limit Orders](/markets-and-trading/limit-orders.md) — control your price with expiration options
* [How Orders Match](/markets-and-trading/matching-logic.md) — price-time priority in detail
* [Category Markets](/markets-and-trading/category-markets.md) — multi-outcome markets
* [Merging & Splitting Shares](/markets-and-trading/merging-and-splitting.md) — convert between USDC and share pairs
* [Market Resolution](/fees-and-settlement/market-resolution.md) — how winning shares pay out
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