Margin Modes: Isolated vs Cross
Isolated caps your loss to one position; cross puts your whole account behind it. When to use each.
Look at the picture above before you read a word. On the left, your money sits behind a wall: the trade can only spend what you put in that box. On the right, every trade drinks from the same pool that is your whole account. That single difference is the entire module.
The one-line version
Isolated margin = you fence off a fixed amount of money for one position. If that trade goes to zero, you lose the fenced amount and nothing else. The rest of your account never gets touched.
Cross margin = your entire available balance stands behind your position(s). More staying power, more flexibility, but a bad trade can reach past its own stake and take the whole account.
Margin, by the way, is just the collateral you lock up to open a leveraged trade. On a perp (a perpetual futures contract, a bet on price with no expiry), that collateral is what keeps the position alive.
Isolated: the loss has a fixed ceiling
Say you have $1,000 in your account. You open a 100x long on BTC and assign $50 of isolated margin to it.
The most that trade can ever cost you is that $50. Price craters, the position liquidates (the exchange force-closes it because the collateral ran out), and you walk away with $950 still sitting in your account, fully usable. The wall did its job.
This is why isolated is the beginner default: it turns every trade into a known, bounded bet. You can look at a position and say "worst case, I'm out $50", and be right.
Cross: more survival, bigger blast radius
Same $1,000, same 100x long, but now in cross mode. There is no $50 fence. The position leans on your whole $1,000.
The upside: it is much harder to liquidate. Price dips against you, the trade automatically borrows staying power from your idle balance, and it rides out a wick that would have killed the isolated version. Pros use cross for exactly this: deeper buffer, and margin flows freely between positions so nothing gets liquidated while spare cash sits idle elsewhere.
The downside is the same fact wearing a mask: if the trade keeps losing, it keeps eating. There is no wall to stop at $50. A single bad position in cross mode can liquidate your entire account.
When to use each
- Use isolated when you want a hard, known cap per trade: degen high-leverage punts, anything you're testing, most of the time as a beginner. One trade blowing up should never touch the rest of your stack.
- Use cross when you're managing a position deliberately and want maximum survivability, and you fully accept that the whole balance is on the line. It rewards discipline and punishes "set it and forget it."
Rule of thumb for your first months: isolated by default. Reach for cross only when you know exactly why you want it.
The trap: "isolated = totally safe"
This is the mistake that catches everyone. Isolated caps your loss: it does not mean the trade is safe from being hit early.
Before a position is fully liquidated, the exchange can do a partial liquidation: it force-closes part of your position to top the margin back up, so you can bleed and lose size even while the trade is technically still open. "Isolated" caps the maximum loss at your assigned margin. It does not promise a smooth ride, and it does not promise you keep your full position size. The wall limits the damage. It doesn't prevent it.
Partial liquidation under isolated: how it actually bites
When your margin ratio crosses the maintenance threshold, many engines don't nuke the whole position at once. They close it in chunks until the remaining position is healthy again.
| Event | What happens to you |
|---|---|
| Margin ratio hits maintenance level | Engine starts closing size |
| Partial close #1 | Part of position gone; realized loss booked; a liquidation fee taken from your isolated margin |
| Price keeps going | More chunks close, each with a fee |
| Margin exhausted | Remaining position force-closed; isolated margin gone |
Net effect: you can exit with less than your assigned margin back (fees), and with a much smaller position than you opened, all while feeling like the trade "was still open." Isolated bounds the worst case; it is not a comfort blanket.
Systemic risk under cross: the hidden chain reaction
Cross margin nets all your positions against one balance. That's efficient, but it couples risks that feel unrelated.
Three positions in cross:
- Position A (BTC long): winning
- Position B (ETH long): flat
- Position C (SOL long): crashing hard
In cross, C's losses draw down the shared equity that's also holding A and B alive. Push far enough and the account's total margin ratio breaches maintenance: the engine can start closing A and B too, even though they weren't the problem. Your winners get liquidated to pay for your loser. Isolated would have quarantined C. Cross let it infect the account.
Switching modes mid-position: a real trap
Most platforms only let you switch between isolated and cross when you have no open position on that symbol (and often no open orders). Trying to flip mid-trade is usually blocked outright.
Where it does something, the direction matters:
- Isolated → cross, mid-position: your position stops being fenced and starts leaning on your whole balance. You may have just removed the wall you opened the trade to have.
- Cross → isolated, mid-position: a fixed margin amount gets carved out for that one position, which can raise its liquidation price and get it killed faster than you expected.
Don't treat the toggle as a rescue button during a losing trade. Decide the mode before you open, size for it, and leave it alone.
Quick knowledge check
In isolated mode, you open a 100x trade with $50 margin in a $1,000 account. What's the most that trade can lose you? $50. The loss is capped at the isolated margin; the other $950 is untouched.
In cross mode, can one losing position liquidate positions that were doing fine? Yes. All positions share one balance, so a big loser can drag the whole account (and your winners) into liquidation.
Does "isolated" mean your position can't be touched until full liquidation? No. Partial liquidation can force-close part of your position early; isolated only caps the maximum loss, not the ride.
Sources
- FINRA, "Margin Regulation": how margin works and the mechanics behind cross and isolated margin.
- SEC (investor.gov), "Understanding Margin Accounts": how a maintenance-margin shortfall triggers forced liquidation.
- CFTC & SEC, "Harmonization of Portfolio Margining Frameworks": mode selection and switching constraints.
- CFTC, "Margin Adequacy Requirements and Separate Account Treatment": when mode changes are and aren't allowed.