Before any leveraged trade, you choose a margin mode: cross or isolated. The choice decides how a losing position interacts with the rest of your account, and getting it wrong is how a single bad trade liquidates everything. It is risk plumbing every leveraged trader must understand.

The core difference

The two modes differ in what backs a position:

  • Isolated margin — only the margin you assign to a specific position backs it. If that position is liquidated, you lose that allocated margin and no more. The rest of your account is walled off.
  • Cross margin — your entire account balance (or a shared pool) backs the position. Losses can draw on the whole balance to avoid liquidation, but a bad enough move can liquidate the entire account.

In short: isolated caps the damage to one position; cross shares the balance across positions to delay liquidation, at the cost of putting everything at risk.

Liquidation implications

This is where it matters most:

  1. Isolated — the liquidation price is tied only to the position's own margin. A wipeout costs you exactly that allocation. Predictable, contained, but the position is liquidated sooner because it has a smaller buffer.
  2. Cross — the whole balance cushions the position, so it can withstand a larger adverse move before liquidation. But if it does liquidate, it can take the entire account with it, including funds you never intended to risk on that trade.

Cross margin's larger buffer is seductive — positions survive deeper drawdowns — but the downside is catastrophic rather than contained.

When to use each

The choice maps to intent and discipline:

  • Isolated suits defined-risk, speculative, or high-leverage trades where you want a hard cap on the loss — "I am risking exactly this much on this idea." It is the disciplined default for most directional bets.
  • Cross suits hedged or market-neutral books where positions offset each other and you want shared margin efficiency, or experienced traders actively managing total account risk. It demands tighter overall risk control because the whole balance is exposed.

A common mistake is running high leverage in cross margin on a single directional bet — that combination means one wrong move can liquidate the entire account.

Practical guidance

  • Default to isolated for individual speculative positions until you have a specific reason not to.
  • Use cross deliberately for offsetting/hedged structures, with explicit account-level risk limits.
  • Never confuse buffer for safety — cross's deeper survival is also deeper exposure.
  • Size for the mode — leverage that is survivable in cross can still wipe the account; leverage that is contained in isolated still loses the allocation.

Takeaway

Isolated margin backs a position only with its assigned margin, capping the loss to that position; cross margin backs it with the whole account, surviving deeper drawdowns but risking total liquidation. Default to isolated for individual speculative trades to contain risk, reserve cross for hedged books with strict account-level limits, and never run high leverage in cross on a single directional bet.