What Is Linear Contract?
A linear contract (or USDT-margined contract) is a derivatives instrument where both margin and PnL are denominated in a stablecoin (typically USDT or USDC). A $1 move in the underlying asset produces a fixed dollar PnL regardless of the underlying asset's price, creating a simple, linear payoff structure.
How Linear Contract Works
Linear contracts simplify trading because: PnL calculation is straightforward ($10,000 notional × 5% move = $500 PnL), margin requirements are stable (your collateral doesn't fluctuate with the underlying), and risk management is intuitive (your position size in stablecoin terms stays constant). This is why linear contracts have become the most popular derivatives format.
Why It Matters for Traders
Linear contracts are preferred for hedging and directional trading where you want clean, predictable exposure without the complexity of inverse contracts. The trade-off is that your collateral (stablecoins) earns no yield while deployed as margin, creating an opportunity cost compared to using the base asset as collateral in inverse contracts.
How It Works on CEX Perps
On centralized perpetual futures venues, linear contract shows up in the position panel, the funding timer, or the liquidation engine rather than as a separate product. Traders usually check it next to mark price, margin mode, and open interest so they do not size a trade from last price alone.
Example numbers only (not a live quote): if you hold a $10,000 notional long with 5x leverage, your initial margin is about $2,000. A move against you of roughly 20% of that notional can push the position near maintenance margin depending on the venue formula. Always read the venue's own liquidation rule before you size.
Formula and Worked Example
Use this only as a labeled example. It is not a live market print.
- Notional = coin size × mark price.
- Initial margin ≈ notional ÷ leverage.
- Distance to liquidation depends on maintenance margin, fees, and whether you use cross or isolated margin.
Example: 0.1 BTC long, mark $60,000, leverage 10x → notional $6,000, initial margin about $600. If maintenance margin is near 0.5% of notional, a modest adverse move can close the trade even when your thesis is still intact.
Common Mistakes
- Treating a single print of linear contract as a trade signal without checking funding, open interest, and your liquidation price.
- Mixing venue conventions (coin-margined vs USDT-margined, cross vs isolated) and reading the wrong mark.
- Copying example numbers from a glossary into live size without checking the current book depth and fee schedule.
- Ignoring related terms that change the meaning of the print on a given day.
