How Liquidation Works on Aster: Margin Tiers, the Trigger and a Worked Example (2026)

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The fee guide tells you what a trade costs. The 1001x guide tells you how far away liquidation sits as a rule of thumb. Neither explains what actually happens between the moment a position is under-margined and the moment it is gone. This page does, using only what Aster's documentation states and what its public endpoints return, and it ends with one BTC position worked to its liquidation price three times so you can see the distance shrink.

What is maintenance margin on Aster?

Maintenance margin is the minimum margin a position must keep to stay open. Aster's margin documentation says two things about it that matter more than anything else on this page:

1. It is based on the total size of the position, not the leverage you select.
2. As position size grows, the higher portions fall into higher maintenance margin tiers, each with a progressively higher rate.

Leverage decides how much initial margin you post. The formula in the docs is (position size × mark price) / leverage. Maintenance margin is a separate number that depends only on notional, so two traders holding the same 10,000 USDT of BTC exposure have the same maintenance margin whether one used 5x and the other used 100x. What differs is how much buffer each has above it.

The tiers themselves are not on the liquidation page of the docs, which points readers to a "Trading Rules" page for fee tiers. They are published by the same public risk-bracket endpoint that the markets hub already uses for its leverage caps. Read on September 15, 2026, the BTCUSDT brackets were:

The "maintenance amount" column is the Binance-style deduction that makes the tiers continuous: maintenance margin = notional × rate − maintenance amount, so a position does not jump in cost the moment it crosses a boundary. Other symbols have their own tables with different rates; a thinner market starts at a higher rate and caps leverage lower, which is why the leverage figure on each market page differs by instrument.

At what point is a position liquidated?

The trigger is stated in the docs as a single inequality:

Margin = Initial Collateral + Realized PnL + Unrealized PnL < Maintenance margin

Three details in the surrounding text change how you should read that line.

The first is that unrealized PnL is measured at the mark price. Aster uses the mark price, not the last trade, to value open positions and to trigger liquidations. The mark price is the median of three numbers: the volume-weighted spot index adjusted for the funding basis, the index plus a 5-minute moving average of the mid-price basis, and the current contract price. A single wick in the contract price does not liquidate you if the index has not moved; a move in the index can liquidate you even if the last trade on Aster has not printed there yet.

The second is that the margin ratio, not the price, is the number to watch. The docs describe liquidation as the point where the risk ratio hits 100% and recommend keeping it below 80%, by adding margin or reducing size. The position panel shows the ratio, the liquidation price and the available balance in real time.

The third is that cross and isolated mode behave differently. Aster uses cross margin by default, so every position's collateral and unrealized PnL support every other position; a winning trade elsewhere raises the margin backing a losing one, and a losing one drains it. In isolated mode only the margin assigned to that position counts. In cross mode with hedge trading, a long and a short in the same contract share one liquidation price; in isolated mode they have separate ones. The margin mode cannot be changed once a position or open order exists.

The docs also list why the liquidation price shown to you keeps moving: funding payments, changes in collateral value, positions opened or closed elsewhere in the account, and cross-margin effects. Funding is the one people miss. Every settlement lands on the position as realized PnL, so a long on a market where longs have been paying for weeks sees its liquidation price creep up without the price of the asset doing anything. The realized settlements per market, over 30 and 90 days, are on the Aster funding rate history page.

Who closes the position, and what does it cost?

Aster's engine does, in a fixed order the docs call a staged, priority-driven process. It is designed to avoid a full close where it can.

1. Cancel every open order on the account, so nothing new can interfere with the flow.
2. Submit one large immediate-or-cancel (IOC) order to reduce the position. It fills as much as the book allows and the rest is canceled. The intention is to eliminate the margin deficit without closing the whole position.
3. Recheck margin, accounting for the realized loss and the liquidation fee. If the remainder meets the maintenance requirement, liquidation stops and what is left of the position stays open.
4. Bankruptcy and insurance-fund takeover. If the IOC could not clear the deficit, the leftover is closed at the bankruptcy price, the protocol price at which the position's margin is exactly exhausted, and handed to the insurance fund. Any profit or remaining assets from handling it stay with the fund.
5. Negative balance handling. If the account is still negative after that, the insurance fund covers the shortfall where it can. If it cannot, auto-deleveraging is triggered against other traders (next section).

Two notes from the docs are worth repeating. Smaller positions have less buffer and are more likely to be fully liquidated, because the partial-close step needs room to work; larger positions get the more gradual, tiered treatment. And in extreme volatility the insurance fund may take over a position directly at the bankruptcy price, which can be worse than the normal liquidation price and cost the trader more.

On cost, the docs state that liquidation involves the realized loss plus a liquidation fee, that a portion of that fee goes to the insurance fund (it appears in the transaction history as "Insurance clear"), and that the fee is calculated from the applicable liquidation fee rate and the notional of the liquidated position. The liquidation page does not publish the rate. The public exchangeInfo endpoint carries a liquidationFee field, which read 0.025000 for BTCUSDT and for 593 of the 594 listed symbols on September 15, 2026. Aster's documentation does not define that field, so this page reports the value and stops there rather than turning it into a dollar figure in the example below. The docs' own advice is the practical version: close manually before the maintenance threshold, reduce leverage, or add collateral, because a manual close pays the ordinary taker fee and a liquidation pays more.

Is there an insurance fund, and what is auto-deleveraging?

Both exist and both are documented, so this section can be specific.

The insurance fund is the account that takes over bankrupt positions and covers negative balances. Its automatic settlement of a negative balance has four conditions, all of which must hold: the negative balance is in a USDT perpetual account, the account has no open positions in either margin mode, the shortfall does not exceed 5,000 USDT, and no funds were transferred in after the liquidation to offset the loss. Outside those conditions the docs direct traders to Discord. The fund is capitalized in part by liquidation fees, and the docs note that positions handed to it may be closed at bankruptcy prices outside the contract's current trading range.

Auto-deleveraging (ADL) is the last resort when the fund cannot cover a loss in time. The ADL page says it is triggered when a liquidation cannot be completed before the mark price reaches the bankruptcy price. The engine then reduces opposite-side positions held by other traders, starting with those that are both most profitable and most leveraged. The ranking is published:

• PnL percentage = unrealized profit ÷ |position notional|
• Effective leverage = |position notional| ÷ (account balance + unrealized profit)
• If PnL percentage ≥ 0, ranking = PnL percentage × effective leverage; if negative, ranking = PnL percentage ÷ effective leverage
• Leverage-PnL quantile = rank ÷ total user count

The higher your quantile, the sooner you are deleveraged. Aster Pro shows it as a four-bar indicator on each position; four bars is high risk. The docs' two ways to reduce it are to lower leverage, or to close and reopen the position, which resets its place in the queue. If you are deleveraged, the position is reduced partially or fully without warning, and you can re-enter afterward. ADL mostly affects traders sitting on large unrealized profits at high leverage, which is to say the traders least expecting to be closed.

Worked example: one BTC long, three leverage settings

The example uses only figures stated above, with the assumptions written down so you can swap in your own. It ignores trading fees and funding, both of which move the real number, and it uses isolated margin so the only collateral is what the position posts. Aster's position panel is the authoritative liquidation price; this is the arithmetic behind it.

The position: long 0.1 BTC, entry 100,000 USDT, so notional = 10,000 USDT. That sits in the second BTCUSDT bracket (400 to 300,000 USDT): maintenance margin rate 0.33%, maintenance amount 1 USDT, maximum leverage in the tier 150x.

The trigger, written out. Liquidation occurs when initial margin plus unrealized PnL equals maintenance margin. For a long, unrealized PnL at mark price P is 0.1 × (P − 100,000). Maintenance margin at that price is 0.1 × P × 0.0033 − 1. So:

IM + 0.1 × (P − 100,000) = 0.1 × P × 0.0033 − 1
IM − 10,000 + 0.1P        = 0.00033P − 1
0.1P − 0.00033P           = 10,000 − IM − 1
0.09967P                  = 9,999 − IM
P                         = (9,999 − IM) ÷ 0.09967

Everything now turns on IM, which is notional ÷ leverage.

At 20x

IM = 10,000 ÷ 20 = 500 USDT.

P = (9,999 − 500) ÷ 0.09967 = 9,499 ÷ 0.09967 = 95,304.50

Liquidation at about 95,305, a 4.70% drop from entry. The rule of thumb says 1 ÷ 20 = 5%; the real distance is shorter because roughly 32 USDT of the 500 posted has to remain as maintenance margin, so only about 468 USDT of it can be lost before the trigger.

At 100x

IM = 10,000 ÷ 100 = 100 USDT.

P = (9,999 − 100) ÷ 0.09967 = 9,899 ÷ 0.09967 = 99,317.75

Liquidation at about 99,318, a 0.68% drop. The rule of thumb says 1%. Now the gap matters: of the 100 USDT posted, 32 must remain, so the position can absorb only 68 USDT of loss. A third of the buffer the leverage number implies does not exist.

At 150x, the tier maximum

IM = 10,000 ÷ 150 = 66.67 USDT.

P = (9,999 − 66.67) ÷ 0.09967 = 9,932.33 ÷ 0.09967 = 99,652.19

Liquidation at about 99,652, a 0.35% drop, against a rule-of-thumb 0.67%. Half the implied buffer is maintenance margin. A normal BTC hour can move that far.

The table leaves out three things that all move the number the same way, against you. Funding settlements land on the position as realized PnL, so on a market where longs have been paying, every settlement moves the liquidation price up by a little (the per-market history is here). Trading fees on entry come out of the same collateral before the position has moved at all. And the arithmetic is for isolated margin; in cross mode the whole account balance stands behind the position, which pushes the liquidation price further away and puts everything else in the account at risk in the same move.

What happens in 1001x mode?

1001x mode is a different product with a different liquidation model, and the docs describe it separately.

Every 1001x position is isolated: it uses its own margin and losses are limited to that position. Positions trade against the ALP liquidity pool rather than the order book, and there is no bracket table. Instead the 1001x fees page gives a closed-form distance:

Liquidation price distance = Entry price × (Initial margin × Liquidation loss rate + Cum funding fee) ÷ Initial margin ÷ Leverage
Long:  Liquidation price = Entry price − distance
Short: Liquidation price = Entry price + distance

The liquidation loss rate is the share of the initial margin the platform lets a position lose before closing it. Here the docs are inconsistent with themselves, and this page will not pick a number for them: the parameter definition says the default is 90%, the worked example on the same page uses 85% (as does a note on the fee page saying the 85% "liquid loss rate" includes the closing fee), and the Degen Mode page states a default of 60%. Whichever applies to your position is reflected in the liquidation price the app shows.

Applying the formula to the same idea as above, a long BTC position with 100 USDT of initial margin at 1001x and no accumulated funding:

At a 90% loss rate: distance = 100,000 × (100 × 0.90) ÷ 100 ÷ 1001 = 89.91  →  liquidation ≈ 99,910 (0.090% from entry)
At an 85% loss rate: distance = 100,000 × (100 × 0.85) ÷ 100 ÷ 1001 = 84.92  →  liquidation ≈ 99,915 (0.085% from entry)

Under a tenth of a percent, either way. Two more rules from the docs shape what you can do about it. At 500x and above, margin cannot be added to an open position, so the only defense is closing it, and the maximum net profit is capped (around 500% at 500x and 750x, around 300% at 1001x). Below 500x you can add margin from the position row. Funding in 1001x mode accrues every block rather than at fixed settlements, and the docs state that it feeds straight into the liquidation price through the accumulated-funding term above. The docs also note that the dynamic closing fee at the top tiers is included in the loss rate, so there is no separate liquidation fee line to add.

How to keep a position away from liquidation

The docs publish their own list. Here it is, with what each item does to the arithmetic above:

• Use lower leverage. It is the only lever that changes the buffer directly: at 20x the position above can lose 468 USDT, at 100x it can lose 68.
• Add collateral. This raises IM without changing notional, so the liquidation price moves away. Not available in 1001x mode at 500x and above.
• Set a stop loss. A stop that triggers before the maintenance threshold pays the ordinary taker fee instead of the liquidation fee and never meets the IOC step.
• Watch funding. On a crowded market the settlements alone erode the buffer; the funding history shows how much per month.
• Avoid oversized positions. Size pushes you into a higher tier with a higher rate and a lower leverage cap at the same time.
• Close before known volatility. Liquidation is a mark-price event, and the mark follows the spot index across several exchanges.

None of this is advice on whether to trade, or at what leverage; it is the mechanism, so that the number in the position panel makes sense before you need it to. Aster is a self-custodial venue with no legal entity named in its terms, and this site is an independent guide with a referral relationship, as set out on the disclaimer. If you have not placed a first trade yet, the step-by-step guide covers the wallet, the deposit and the order ticket, and the 1001x guide covers the one-click mode in full.

Sources & Citation

How these figures were verified

• Aster official documentation: Liquidations (Perpetuals, Fees & Specs) — the trigger condition, the mark-price rule, the five-step liquidation process, the bankruptcy price, the insurance fund, the 5,000 USDT automatic settlement conditions, the 80% margin-ratio recommendation and the description of the liquidation fee. Checked September 15, 2026.
• Aster official documentation: Auto-Deleveraging (ADL) — when ADL triggers, the PnL-percentage and effective-leverage ranking formulas, and the four-bar indicator. Checked September 15, 2026.
• Aster official documentation: Margin — the initial margin formula, cross versus isolated mode, and the statement that maintenance margin depends on position size rather than leverage. Checked September 15, 2026.
• Aster official documentation: Mark Price — how the mark price is built from the price index, the 5-minute basis average and the contract price, and why it is the liquidation reference. Checked September 15, 2026.
• Aster official documentation: 1001x Fees & Slippage and Degen Mode — the 1001x liquidation-distance formula, the liquidation loss rate figures of 90%, 85% and 60%, and the rule that margin cannot be added at 500x and above. Checked September 15, 2026.
• Aster risk-bracket endpoint — the BTCUSDT maintenance margin tiers, maintenance amounts and per-tier leverage caps used in the table and the worked example (a POST request with an empty JSON body; the same endpoint the leverage caps on /markets come from). Checked September 15, 2026.
• Aster public futures API: exchangeInfo — the liquidationFee field of 0.025000 reported for BTCUSDT and 593 of the 594 listed symbols. Checked September 15, 2026.
• Asterpedia — the worked example, derived line by line from the trigger condition and the bracket rates above, with the assumptions stated. Checked September 15, 2026.

Aster revises its fee schedules, leverage caps and token mechanics regularly, so every figure here is a dated snapshot rather than a live feed. Where a number comes from Asterpedia’s own tracking rather than the documentation, it is labelled as such above.

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Asterpedia. "How Liquidation Works on Aster: Margin Tiers, the Trigger and a Worked Example (2026)." Published September 15, 2026; last updated September 15, 2026. https://asterpedia.com/guides/trading/how-liquidation-works-on-asterCopy

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