Perps trading depends on how order fills create or change positions, how prices
affect account equity, and how collateral supports trading risk. The concepts
below describe the moving parts that determine what an account can trade and when
a position is at risk.
Instruments
An instrument identifies a Perps market: a tradable perpetual contract that
tracks an underlying asset such as the S&P 500 Index, gold, or bitcoin. Each
instrument carries the information needed to identify the market and the rules
for trading it.
| Attribute | Meaning |
|---|
| ID | The instrument identifier used in market data and orders |
| Symbol | A short market label, such as SP500-USD, GOLD-USD, or BTC-USD |
| Underlying asset | The asset or index the market tracks, such as the S&P 500 Index, gold, or bitcoin |
| Collateral asset | The asset used to fund Perps accounts and support open positions. Polymarket Perps use pUSD. |
| Trading constraints | Market-specific rules such as price precision, quantity precision, order limits, and leverage. |
Perps Accounts
A Perps account is tied to a signer account. The signer account controls private
actions such as trading and withdrawals.
The Perps account holds the state created by those actions: collateral, open
positions, orders, fills, and history. Later sections explain how those pieces
change as orders execute, prices move, and funding payments settle.
Perps accounts are funded through onchain collateral deposits.
If you’re building on Perps, delegated credentials let your app act for the
Perps account without using the owner key for every private action. See
Authenticated Sessions. Prices
A Perps market has two broad categories of prices: execution prices and
calculated prices. Execution prices come from trades in the order book.
Calculated prices are produced by Polymarket and used for reference, margin, and
liquidation checks.
This separation matters because one small or isolated trade should not be able to
change an account’s risk state or trigger liquidation by itself.
| Price | Category | Meaning | Used for |
|---|
| Traded price | Execution price | The price of an executed order book fill | Trade history and execution records |
| Index price | Calculated price | Polymarket’s estimate of the underlying asset’s fair value | Reference price and price anchoring |
| Mark price | Calculated price | The price used to value positions | Unrealized PnL, margin checks, and liquidation risk |
Orders And Fills
Orders are requests to trade in a Perps market. They can execute immediately or
rest in the order book until another order matches them.
The order book is the list of resting buy and sell orders for a market. A fill is
an executed match between orders in that book.
Fills update Perps account state; they are not separate onchain transactions.
Trading Positions
Once an order fills, it changes the account’s position in that market. A position
is what the account currently holds: long exposure, short exposure, or no open
exposure.
| Position | Benefits when | Loses when |
|---|
| Long | The tracked asset rises | The tracked asset falls |
| Short | The tracked asset falls | The tracked asset rises |
Margin And Liquidation
Perps accounts use collateral to support open positions. Margin checks compare
the account’s current value against the collateral required to open, increase, or
maintain those positions.
Margin checks use these terms:
| Term | Meaning |
|---|
| Collateral | Funds available to support positions and withdrawals |
| Account equity | The current value of the account after open-position gains, losses, fees, and funding effects |
| Initial margin | Collateral required to open or increase a position |
| Maintenance margin | Minimum collateral required to keep a position open |
| Liquidation | Forced position closing when account equity falls below maintenance margin |
If you’re building on Perps, monitor account equity to decide when to reduce
exposure, add collateral, or stop placing new orders.
Account equity = collateral + unrealized PnL - amounts owed
Funding Payments
Funding payments help keep a Perps market close to its index price. They are
not order-book trades; they are account debits or credits applied to open
positions over time.
Funding payments are different from collateral deposits. Deposits add
collateral to a Perps account; funding payments are debits or credits between
long and short positions.
| Market state | Typical payment direction |
|---|
| Market trades above index price | Longs pay shorts |
| Market trades below index price | Shorts pay longs |
Realtime Account State
If you’re building on Perps, realtime account state helps your integration keep a
local view in sync.
Integrations often keep a local view of account state so they can react quickly
to fills, risk changes, and collateral movements. Realtime updates help keep that
local view in sync.
| State change | Why it matters |
|---|
| Order update | A resting order opened, changed, filled, or cancelled |
| Fill | A trade executed and changed the account’s position or balance |
| Portfolio update | Account equity, margin, or position state changed |
| Funding payment | A funding debit or credit changed account state |
| Deposit or withdrawal | Collateral moved into or out of the account |
