A
Arbitrum
Arbitrum is a Layer 2 Ethereum scaling network that executes transactions off-chain and settles them on Ethereum mainnet, reducing gas costs to approximately $0.01 per trade while maintaining full Ethereum security. Ostium deploys exclusively on Arbitrum.Ask Price
Ask price is the current market price at which you can buy an asset. Longs open at the ask and shorts close at the ask. On Ostium, the ask is derived from the oracle feed plus any applicable spread or price impact.Auto-Close
Auto-close is the automatic closure of stock positions held above the overnight leverage cap at 3:45 PM ET, 15 minutes before regular market close. Positions at or below the overnight cap can be held across market sessions. See Stocks: Day Trading.B
Backwardation
Backwardation occurs when the underlying asset’s futures curve slopes downward: distant contracts trade below near-term contracts or spot. On Ostium, backwardation in the underlying lowers the long-side rollover rate and raises the short-side rate; longs may collect rollover on deeply backwardated pairs (see Contango, Rollover Fee).Bid Price
Bid price is the current market price at which you can sell an asset. Shorts open at the bid and longs close at the bid. On Ostium, the bid is derived from the oracle feed minus any applicable spread or price impact.Broker Premium
Broker premium is a flat 1–2% annualized markup added to the rollover fee on all pairs. The total rollover fee equals the underlying market carry rate plus the broker premium. See Fees.Buffer
The buffer is the junior tranche of the Ostium Vault: dedicated capital posted by Ostium Labs and strategic partners that sits in the vault smart contract alongside OLP capital. The buffer absorbs trader PnL first, in full, before any loss can reach OLP. Rebalanced to its target size once per day at daily settlement. See Vault Overview.Builder Codes
Builder codes are referral identifiers that allow affiliates and integrators to track referrals and earn commission on trading fees from referred users.C
Chainlink
Chainlink is a decentralized oracle network providing tamper-proof real-time price data for onchain use. Ostium uses Chainlink Low-Latency feeds for crypto asset pricing.Collateral
Collateral is the USDC a trader commits to open a leveraged position. Position size equals collateral multiplied by leverage. If unrealized losses erode collateral below the liquidation threshold, the position is liquidated (see Liquidation). Collateral is locked in the protocol contracts while a position is open and returned (adjusted for PnL) on close; keys and approvals remain under the trader’s control throughout.Contango
Contango occurs when the underlying asset’s futures curve slopes upward: distant contracts trade above near-term contracts or spot. On Ostium, contango in the underlying raises the long-side rollover rate; shorts may collect rollover on deeply contango pairs (see Backwardation, Rollover Fee).Carry Cost
Carry cost is the economic cost of holding a position in an underlying asset, derived from interest rates, futures term structure, and funding-rate markets. Ostium’s rollover fee reflects the carry cost of each asset class plus a broker premium. See Fees.C-Ratio
C-ratio (collateral ratio) is the ratio of total vault collateral to total open position notional value. A legacy metric from the pre-upgrade vault model where c-ratio determined Overcollateralized (OC) and Undercollateralized (UC) states. Post-upgrade, directional trader flow is hedged offchain and OLP sits in the senior loss position behind a dedicated buffer, so c-ratio is no longer the primary driver of LP yield or vault state. See Vault Overview.D
Daily Settlement
Daily settlement is the once-per-day reconciliation between the onchain Ostium Vault and the offchain hedging book. During the day, winning trades are paid onchain from the vault while their offchain hedges accrue equal and opposite gains; losing trades are retained onchain while their offchain hedges take the matching loss. At settlement, USDC flows between the two books to restore the buffer to its target size. OLP price recomputes at settlement. See Vault Overview.Day Trading Leverage
Day trading leverage is the higher leverage tier available on stocks during market hours (9:31 AM – 3:45 PM ET), up to 100x or the pair’s maximum. Positions using day trading leverage auto-close at 3:45 PM ET. See Stocks: Day Trading.Dynamic Spreads
Dynamic spreads are variable bid-ask spreads that adjust based on short-term order flow imbalance. Currently enabled for all crypto and stock pairs on Ostium. Under balanced conditions, dynamic spreads apply zero spread; when order flow becomes one-sided, spreads widen to reflect the imbalance. Trades on pairs with dynamic spreads execute at a Price-After-Impact rather than the raw bid/ask (see Price-After-Impact).E
ETF
An Exchange Traded Fund (ETF) is a basket of underlying assets that trades on an exchange. Ostium offers perpetual instruments on URA (uranium), KR2550 (Korean stock index), UNG (natural gas), and XLE (energy), with leverage up to 50x. See Markets.Execution Model
Execution model describes how Ostium executes trades. Prices are sourced from Chainlink (crypto) or Stork (real-world assets). Orders, liquidations, and automated TP/SL are executed by decentralized keepers via Chainlink Automations and Gelato Functions, without a central operator.F
Funding Fee (Deprecated)
Funding fees were previously used on crypto pairs as a zero-sum payment between longs and shorts based on OI imbalance. This mechanism has been removed. All pairs now use rollover fees (see Rollover Fee).G
Gas
Gas is the transaction fee paid to execute onchain operations. On Arbitrum, gas costs are typically under $0.01 per transaction. Web3 wallet users pay gas in ETH; email login users trade gas-free, as the platform sponsors their transactions.Gelato Functions
Gelato Functions is a decentralized automation service that executes smart contract functions reliably and cost-efficiently. Ostium uses Gelato to execute liquidations, stop-losses, and take-profits without a central operator.H
Hedging Partner
An institutional counterparty that absorbs the directional risk of trades opened on Ostium. When a trade opens onchain, it is mirrored offchain through a network of hedging partners, with Jump Trading as flagship hedging partner, joined by prime brokers and other major institutional partners. Partners supply pricing from the most liquid underlying markets. See How Ostium Works.J
Junior Tranche
In structured credit, the junior tranche absorbs losses first, protecting the senior tranche above it. On Ostium, the buffer is the junior tranche: it takes trader PnL in full before any loss can reach OLP (the senior tranche). See Buffer, Senior Tranche, and Vault Overview.K
Keeper
A keeper is an external service or bot that monitors trading conditions and executes transactions like liquidations or stop orders. On Ostium, keepers are automated via Chainlink Automations and Gelato Functions.L
Leverage
Leverage is a multiplier applied to collateral to determine position size. A trader with 100 USDC collateral and 10x leverage controls a 1,000 USDC notional position. Higher leverage amplifies both gains and losses. Ostium supports leverage from 1x up to 200x depending on the pair.Limit Order
A limit order is an instruction to open a position at a specified price or better. The order executes automatically when the bid/ask reaches the limit price. Canceling a pending limit order incurs an oracle fee. See Order Types.Liquidation
Liquidation is the automatic closure of a position when collateral falls below the liquidation threshold. Keeper bots execute liquidations onchain; the protocol pays the gas. All remaining collateral is retained by the protocol as part of settlement. There is no margin call. See Liquidation.M
Margin
Margin is the collateral required to hold a position. Initial margin is the collateral needed to open. If unrealized losses bring collateral below the liquidation threshold, the position is liquidated.Market Order
A market order executes immediately at the current bid (for shorts) or ask (for longs). Market orders are the standard way to enter or exit a position when you want to execute right away.Mid-Price
Mid-price is the midpoint between the bid and ask. It is used as a reference for triggering stops, stop-losses, and liquidations, but trades never actually execute at the mid-price; execution always happens at the bid or ask.N
Net Rate (L/S)
Net Rate (L/S) is the label in the trading interface that displays the current rollover rate for both long and short positions on a pair. A positive rate means that side pays; a negative rate means that side collects.Non-Custodial
Non-custodial means users retain full control of their keys and approvals at all times. Collateral moves into protocol smart contracts only when a position is opened and is returned (adjusted for PnL) on close; Ostium has no ability to move user funds outside that flow.Notional
Notional is the total size of a leveraged position, equal to collateral multiplied by leverage. A 100 USDC position at 10x leverage has a notional of 1,000 USDC. Opening fees, rollover fees, and PnL scale with notional. Also called position size.O
OI (Open Interest)
Open interest is the total cumulative notional value of all open positions on a particular asset and side (long or short). High OI indicates liquidity and trader activity.OI Cap
OI cap is the maximum notional open interest allowed for a pair, managing the protocol’s risk envelope and the hedging layer’s capacity. When the cap is reached, no new positions in that direction can be opened until existing positions are closed.OLP
OLP (Ostium Liquidity Provider token) is the ERC-20 received by LPs who deposit USDC into the Ostium Vault. OLP holds the senior loss position of the protocol: a dedicated buffer of junior capital absorbs trader PnL first, in full, before any loss can reach OLP. OLP earns yield from a fixed share of opening fees. OLP price recomputes once per day at daily settlement. See OLP Token.Opening Fee
The opening fee is charged when a trader opens a position. Calculated on notional (collateral × leverage) and deducted from collateral. Rates range from 3 to 20 bps depending on asset class and pair. A fixed share of opening fees flows to OLP holders at daily settlement; the remainder funds protocol operations. See Fees.Oracle
An oracle is a decentralized service that supplies real-time price data for onchain use. Ostium uses Chainlink for crypto and Stork for real-world assets (stocks, commodities, forex, indices).Oracle Fee
The oracle fee is a flat $0.10 USDC charge each time the protocol fetches an onchain price. Charged at position open and refunded on a successful full close. Not charged on automated TP/SL executions. See Fees.One-Click Trading (1-Click)
One-click trading pre-approves transactions so trades execute without a wallet prompt for each order. Enabled by default on email (smart account) logins. Web3 wallet users can enable it in profile settings; doing so requires a one-time approval transaction.Overcollateralized (OC) — Deprecated
Overcollateralized (OC) described a vault state from the pre-April 2026 model when c-ratio exceeded 100%. Retained here for historical reference only. Post-upgrade, OLP sits in the senior loss position behind a dedicated buffer, and the vault’s state is described as Normal (buffer intact, OLP protected) or UC (buffer depleted). See Vault Overview.Overnight Leverage
Overnight leverage is the lower leverage cap applied to stock positions held past market close (typically 5x–20x, varies by stock). Positions above the overnight cap auto-close at 3:45 PM ET. See Stocks: Day Trading.P
Partial Close
A partial close exits a portion of an open position while keeping the rest active. Each partial close incurs an oracle fee ($0.10). The remaining position must meet the pair’s minimum trade size.Perpetual Instrument
A perpetual instrument is a leveraged derivative that provides price exposure to an underlying asset without expiration, delivery, or ownership of the asset itself. Unlike traditional futures contracts, perpetual instruments have no expiry date and no physical or cash-settled delivery. Ostium’s perpetual instruments are fully collateralized in USDC, settled onchain, and priced from oracle feeds on the underlying market. They are not futures contracts and are not regulated as such.Price-After-Impact
Price-after-impact is the execution price on pairs with dynamic spreads enabled. It reflects short-term order flow imbalance: zero spread under balanced conditions, wider spread when flow becomes one-sided. See Dynamic Spreads.Privy
Privy is the account infrastructure provider that powers Ostium’s email login. Privy manages smart account creation and authentication without holding user funds or keys.R
Rollover Fee
Rollover fee is the cost of holding any position over time. Derived from the underlying asset’s carry cost (SOFR for stocks, ETFs, and indices; futures term structure for commodities and forex; funding rates and futures term structure for crypto) plus a broker premium. Rollover is two-sided on every pair: depending on the shape of the underlying carry, one side can collect rollover rather than pay. Fees accrue continuously per block and are collected by the protocol. See Fees and Vault Overview for how fees reconcile at daily settlement.S
Senior Tranche
In structured credit, the senior tranche is the safest layer of a capital stack. Losses must chew through the junior layers beneath it before any can reach senior capital. On Ostium, OLP is the senior tranche of the vault, protected by the buffer (the junior tranche). This is the same subordination architecture used in CLOs and clearinghouse default waterfalls. See Buffer, Junior Tranche, and Vault Overview.Settlement
Settlement has two meanings on Ostium: Position-level settlement is the realization of PnL and return of collateral to the trader’s wallet when a position closes. This happens instantly and onchain. Daily settlement is the once-per-day reconciliation between the onchain Ostium Vault and the offchain hedging book, at which point USDC flows between the two books to restore the buffer to its target size. OLP price recomputes at daily settlement. See Vault Overview.Slippage
Slippage is the difference between the expected execution price and the actual execution price, caused by spreads and market movement between submission and execution. Traders can set slippage tolerance to limit unintended price movements.Smart Account
A smart account is a programmable wallet managed onchain. Ostium’s email login creates a smart account for each user, enabling gasless transactions and 1-click trading. The user retains full control; Privy provides the infrastructure without accessing keys.SOFR
SOFR (Secured Overnight Financing Rate) is the benchmark interest rate published by the Federal Reserve reflecting overnight lending costs. Ostium uses SOFR plus broker premium to compute rollover for stocks, ETFs, and indices. Commodities and forex use futures term structure; crypto uses funding rates and futures term structure.Spread
Spread is the difference between the bid and ask price. A wider spread means higher execution costs. On Ostium, spreads reflect underlying market liquidity; on pairs with dynamic spreads enabled, spreads also adjust with short-term order flow imbalance.Stop-Loss (SL)
Stop-loss (SL) is an order that automatically closes a position when the mid-price crosses a specified level, limiting losses. Executes as a market close at the bid/ask. Free to set and adjust. No oracle fee on automated execution.Stork
Stork is a decentralized oracle network supplying real-world asset prices (stocks, commodities, forex, indices) via aggregation of traditional-market data feeds. Stork operates independently from Ostium and updates prices on a sub-second basis.Supported Assets
Ostium supports 60 trading pairs across six asset classes: 24 stocks, 4 ETFs, 7 commodities, 7 indices, 9 forex, and 9 crypto. Each pair is a perpetual instrument with leverage from 1x up to 200x (varies by pair). See Markets.T
Take-Profit (TP)
Take-profit (TP) is an order that automatically closes a position at a target price to lock in gains. Executes as a limit close at the TP price. Maximum TP is 900% above entry (entry × 10). Free to set and adjust. No oracle fee on automated execution.Term Structure
Term structure refers to the relationship between spot prices and futures prices across different time horizons in the underlying market. For Ostium’s perpetual instruments, the underlying term structure is reflected in rollover rates. Contango signals upward term structure; backwardation signals downward term structure.U
Undercollateralized (UC)
Post-upgrade, UC describes a state in which the vault’s buffer has been fully depleted and additional trader PnL losses begin drawing on OLP capital. During UC, the vault automatically blocks new deposits as an accounting measure (pending-loss deposits would create share-pricing ambiguity). Ostium Labs’ operational priority in UC is to restore the buffer and return the vault to normal state. See Vault Overview. Pre-upgrade, UC had a different meaning tied to c-ratio; that framing no longer applies.USDC
USDC is a fully-collateralized US dollar stablecoin issued by Circle. Ostium uses USDC as the sole collateral and settlement asset, allowing traders and LPs to maintain dollar-denominated exposure without conversion overhead.V
Vault
The Ostium Vault is the onchain settlement layer for every trade on the protocol. It holds two distinct pools of USDC: OLP capital (the senior tranche, deposited by LPs) and buffer capital (the junior tranche, posted by Ostium Labs and strategic partners). Losses flow in strict order: the buffer absorbs trader PnL first, in full, before any loss can reach OLP. During the day, the vault pays winning trades immediately onchain; at daily settlement, USDC is rebalanced against the offchain hedging book to restore the buffer to its target size. See Vault Overview.Cross-Reference Summary
Position Management: Leverage, Collateral, Margin, Notional, Position Size, Liquidation, Stop-Loss, Take-Profit, Limit Order, Market Order, Partial Close Pricing & Execution: Oracle, Ask Price, Bid Price, Mid-Price, Spread, Price-After-Impact, Slippage, Dynamic Spreads, Execution Model Fees & Costs: Opening Fee, Oracle Fee, Rollover Fee, Broker Premium, Net Rate (L/S) Vault & Collateral: Vault, Buffer, OLP, Senior Tranche, Junior Tranche, Daily Settlement, Settlement, Collateral, Undercollateralized (UC), Overcollateralized (deprecated), C-Ratio (deprecated) Hedging & Carry: Hedging Partner, Carry Cost, Rollover Fee, SOFR, Term Structure, Contango, Backwardation Assets & Markets: ETF, Perpetual Instrument, OI, OI Cap, Term Structure, Contango, Backwardation, Supported Assets Stock Trading: Day Trading Leverage, Overnight Leverage, Auto-Close Accounts & Access: Smart Account, Non-Custodial, Privy, One-Click Trading, Gas Services & Integration: Gelato Functions, Keeper, Builder Codes Standards & Infrastructure: Arbitrum, USDC, Chainlink, Stork, SOFRWhat to Read Next
- Fees — Fee structure and calculations.
- Markets — Trading pairs and asset availability.
- Order Types — All order types and execution mechanics.