Crypto Derivatives Structure: Linear, Inverse, Quanto, and What Each Actually Costs You

A "BTC perpetual" can mean several different contracts depending on the exchange and contract type. Linear perps, inverse perps, USDC-margined, BTC-margined, USDT- quoted, USD-quoted, each has different PnL math, different collateral requirements, and different risks. Most retail traders click "BTC-USDT" without realizing which structure they're actually trading. The differences matter for sizing, hedging, and PnL calculation.

The three main structures

1. Linear (USDT-margined or USDC-margined).

Contract: BTC-USDT or BTC-USDC perpetual. Quoted in: USD-equivalent Settled in: USDT or USDC (stablecoin) PnL math: linear in USD terms (a $1 move in price = $X PnL where X is your contract size in USD)

This is the most retail-friendly structure. Your collateral is in stablecoins; PnL is in stablecoins; the math is intuitive (you make/lose dollars per dollar of price move).

2. Inverse (BTC-margined or coin-margined).

Contract: BTCUSD inverse perpetual. Quoted in: USD Settled in: BTC (the underlying coin) PnL math: non-linear, your PnL in BTC terms depends on both the price move AND the price level

This is the historical structure (BitMEX invented it). Your collateral is BTC; PnL is in BTC; the math is non-intuitive because both your collateral's value AND your position's PnL move with price.

Worked example: 1 BTC short of inverse BTCUSD at $70,000.

• If BTC falls to $60,000: you "win" $10,000 USD worth, but in BTC terms it's $10,000 / $60,000 ≈ 0.167 BTC. Your collateral (1 BTC) is now worth less in USD, but your BTC balance grew.
• The non-linearity is significant, inverse contracts behave differently from linear ones at the same notional.

Inverse contracts are what professional traders use for "BTC-denominated" PnL exposure. For most retail, linear is more straightforward.

3. Quanto (rare in crypto).

Settlement currency different from both quote and underlying. Used in some specialized contracts. Generally not relevant for retail.

Why the structure matters

Several practical implications:

1. Your "true" exposure depends on structure. A 1 BTC linear position has $X USD of price exposure. A 1 BTC inverse position has the same notional but different PnL behavior because of the inverse math. The "1 BTC" doesn't mean the same thing.

2. Collateral risk differs. Linear with USDT collateral: your collateral is at risk of stablecoin depeg. Inverse with BTC collateral: your collateral fluctuates with BTC price (it's the asset you're trading). The collateral risk is different in nature.

3. Hedging math is non-trivial. If you want to hedge a spot BTC position with a short perp:

• Linear: 1 BTC of perp short hedges 1 BTC of spot cleanly (in USD terms)
• Inverse: 1 BTC of perp short hedges differently; the hedge ratio depends on price (and changes as price changes)

For basis trades and other hedging strategies, the structure affects how clean the hedge is.

4. Liquidation behavior differs. Inverse contracts have liquidation math that depends on the BTC price (your collateral's value). Linear contracts have simpler USD-based liquidation math.

For the same nominal leverage, the practical risk profile differs.

5. Funding rate calculations may differ. Funding is generally similar across structures but subtle differences exist. Verify on the specific venue.

How to identify which structure you're using

On most exchanges:

• "BTCUSDT perp" or "BTCUSDC perp" = linear, USDT or USDC margined
• "BTCUSD perp" without the trailing T = inverse, BTC margined (sometimes labeled "coin-margined" or "inverse")
• The collateral / margin balance shown tells you what you're posting
• The PnL displayed in the position panel shows you the settlement currency

When in doubt, check the contract specifications. Don't assume; verify.

Cross-margin vs isolated within these structures

Both linear and inverse can be traded in cross or isolated margin (per the isolated-vs-cross-margin chapter):

• Linear cross: all your stablecoin collateral defends all your stablecoin-margined positions
• Linear isolated: each position has dedicated stablecoin collateral
• Inverse cross: all your BTC collateral defends all your BTC-margined positions
• Inverse isolated: each position has dedicated BTC collateral

Some exchanges have unified margin that pools all your collateral (across stables and crypto) as collateral for all positions. Most capital-efficient but most operationally complex.

For most retail starting out, isolated linear with stablecoin collateral is the simplest and safest structure to learn on.

A common mistake: mixing linear and inverse without realizing

A trader has spot BTC and wants to hedge with a perp short. They click "BTCUSD" thinking it's the same as their spot. It's actually inverse. The hedge math doesn't work the way they expected.

The fix: read the contract specifications. The "USDT" suffix usually indicates linear; bare "USD" often indicates inverse. When in doubt, ask the exchange's support or read their derivatives docs.

A common mistake: thinking "inverse" is just a different ticker

Inverse contracts have fundamentally different math. The non-linearity in BTC terms means hedging, sizing, and PnL calculation all work differently. Treating inverse as "the same as linear but with BTC collateral" misses the structural difference.

The fix: if you trade inverse, take the time to understand the math. Use the exchange's risk calculators. Practice with small positions until the behavior is intuitive.

A common mistake: not accounting for collateral risk type

A trader posts USDT as collateral on a linear contract. They think they're "in dollars." But USDT has depeg risk, issuer risk, and chain-specific risk. Their collateral isn't pure USD.

A trader posts BTC as collateral on an inverse contract. They have BTC-denominated risk on the collateral side that adds to (or offsets) their position-side risk.

The fix: be aware of what your collateral actually is. Treat collateral risk as a separate dimension from position risk. Diversify across collateral types when appropriate.

A common mistake: confusing notional value

A trader has a "1 BTC perp" position. They think their exposure is one BTC. But the exposure depends on contract structure:

• Linear 1 BTC: ~$67,000 USD exposure (at current prices)
• Inverse 1 BTC equivalent: depends on contract multiplier and current price

The PnL behavior of "1 BTC" of position differs between structures.

The fix: think in USD notional (or your settlement currency), not in BTC units. The USD notional is what determines your PnL behavior consistently.

The other dimensions: dated vs perpetual

Beyond linear/inverse, contracts can be:

Dated futures. Expire on a specific date. Settlement at expiration. No funding rate; basis implicit in price differential between futures and spot.

Perpetual futures. Never expire. Funding rate keeps price tethered to spot.

In crypto, perpetuals are far more common than dated futures. Both follow the linear/inverse split, there are linear perpetuals, inverse perpetuals, linear dated futures, and inverse dated futures.

Options structure too

Options have their own structural variations:

European vs American style. European options can only be exercised at expiration; American can be exercised anytime. Most crypto options are European.

Cash-settled vs physically-settled. Cash-settled options pay PnL in cash at expiration; physically- settled deliver the underlying asset. Most crypto options are cash-settled.

Inverse vs linear options. Same dynamic as perps, some options settle in BTC (inverse), some in USDT/ USDC (linear). Deribit's main options are inverse- settled in the underlying.

The structural variations affect PnL math the same way they do for perps. Read the specifications.

Mental model, derivatives structure as the contract's currency

Every contract has a "currency", the unit in which PnL is denominated. Linear contracts are denominated in stablecoins (a dollar move = a dollar of PnL). Inverse contracts are denominated in the underlying asset (a dollar move = a fractional asset of PnL, where the fraction depends on the asset's price).

Traders who think in dollars find linear intuitive and inverse confusing. Traders who think in asset-denominated terms (e.g., institutional traders who care about "increasing my BTC stack") find inverse intuitive and linear less natural.

For most retail in crypto, linear (USDT/USDC margined) is the right starting point. The math is intuitive and the collateral is in something that behaves like dollars (modulo stablecoin risk).

Why this matters for trading

Knowing which structure you're trading prevents the unpleasant surprises (hedge math failing, PnL not matching expectations, collateral behaving differently than expected) that catch derivatives beginners. Hex37's perpetual support is linear by default, making the math intuitive while you learn. For more advanced strategies (especially basis trading with inverse-spot offsets or multi-currency positioning), understanding the structures becomes critical.

Takeaway

Crypto derivatives have multiple structures. Linear (USDT/USDC-margined) has straightforward USD- denominated PnL, the right starting point for most retail. Inverse (BTC-margined) has non-linear PnL math because both collateral and position move with price used by professional traders for asset-denominated exposure. Quanto and other variants are rare and specialized. Mixing structures or hedging across them requires careful math. Read contract specifications. Understand your collateral risk. Think in USD notional for consistency. The structure is part of the contract, not an interchangeable ticker.