how Binance partial liquidation steps a position down the margin tiers

Binance can partially liquidate a position whose notional sits above the first maintenance-margin bracket. instead of closing the entire position immediately, the engine reduces notional, checks the bracket again and applies the lower MMR available to the survivor. that lower MMR moves the survivor’s estimated liq away from entry, provided the live margin left after realised loss and fees supports it.

the mechanism is a bracket step, not a reversal of the liquidation event. for BTC USDT-M isolated margin, notional above $800,000 and up to $3,000,000 occupies the third listed bracket at 0.65% MMR. reducing that position to $800,000 lands it in the second bracket at 0.5% MMR. the remaining position is still exposed, but its maintenance requirement is lower.

liq is assessed against mark rather than whether the last-price wick printed through a line on your chart. the displayed or calculated level can also move during the event because notional, maintenance margin, remaining margin, fees and realised PnL have changed. estimate — exchanges compute exact liq from live margin; always double-check on your venue.

Binance’s BTC ladder raises MMR as notional crosses each bracket. the first $300,000 bracket carries 0.4% MMR and permits up to 150x, while the fifth listed bracket reaches $70,000,000, carries 2% MMR and permits up to 25x. partial liquidation works down this ladder by reducing the position’s notional into a lower band.

the important boundary for the worked event is $800,000. a BTC position at or below that amount is in the second bracket with 0.5% MMR; a position above it, through $3,000,000, is in the third bracket with 0.65% MMR. the MMR change is 0.65% − 0.5% = 0.15 percentage points.

take a Binance BTC long with a $97,400 entry, $1,000,000 notional and 20x effective leverage. because $1,000,000 is above $800,000 but below $3,000,000, the position starts in the third bracket at 0.65% MMR. before any loss or fee adjustment, $1,000,000 ÷ 20 gives $50,000 of initial margin.

using the isolated approximation, long liq = entry × (1 − 1/leverage + MMR). the starting estimate is $97,400 × (1 − 1/20 + 0.0065) = $93,163.10. that is $97,400 − $93,163.10 = $4,236.90 below entry, or 4.35% of the $97,400 entry.

if the engine closes $200,000 of notional, the survivor is $1,000,000 − $200,000 = $800,000 and fits the second bracket. holding entry and effective leverage constant to isolate the bracket effect, estimated liq becomes $97,400 × (1 − 1/20 + 0.005) = $93,017. the lower MMR adds $146.10 of downside room.

the survivor’s liq is recalculated after the partial close because the position and margin account no longer match their pre-event state. the bracket-only calculation moves the long liq from $93,163.10 to $93,017, while the equivalent short estimate moves from $101,636.90 to $101,783. for either side, the 0.15-percentage-point MMR reduction creates $146.10 of additional price distance at a $97,400 entry.

that clean $146.10 shift is not necessarily the line shown after a live liquidation. the closed piece realises a loss, the liquidation step incurs a fee, and funding or other venue accruals may already have changed margin. those deductions alter effective leverage and can offset some of the room created by dropping from 0.65% MMR to 0.5% MMR.

cross margin makes the estimate less portable because unrealised PnL and available collateral elsewhere in the account can affect the live calculation. the liqsiren isolated formula deliberately ignores unrealised PnL on other positions and the exchange’s own fee and funding accruals since entry. the live venue calculation, not the static bracket comparison, controls the actual event.

no bracket step is available below the first bracket. a Binance BTC position at or below $300,000 already uses the lowest listed BTC MMR of 0.4%, so reducing it cannot move the survivor into another lower maintenance tier. the position therefore does not get stepped down through the bracket ladder in the way a third-bracket position can be reduced into the second.

a $10,000 Binance BTC position is well inside that first bracket. at the worked $97,400 entry and 20x leverage, its estimated long liq is $92,919.60, leaving $4,480.40 or 4.6% below entry. because both $10,000 and any smaller survivor remain under $300,000, partial closure cannot produce an MMR reduction below 0.4%.

partial liquidation has already crystallised damage. for a long, the closed slice realises the difference between its entry and adverse execution price; for a short, the direction is reversed. the step also pays a liquidation-related fee or charge whose exact amount is venue- and tier-dependent. the remaining position gets a lower MMR, but the closed notional and deducted margin are not restored.

ordinary taker costs show why repeated execution matters even before adding any separate liquidation charge. Binance’s stated taker fee in the facts used here is 0.05%, making a taker round trip 0.1% of notional. at 20x, that round trip equals 2% of posted margin; at 50x it equals 5%, and at 100x it equals 10%.

funding can add another margin deduction or credit while a position remains open. Binance funding intervals in this pack are 8 hours, but the applicable rate is not fixed here. because the exact liq reflects live margin, a funding debit before or during stress can pull the venue’s line closer even when a bracket reduction pushes the maintenance component farther away.

position size determines whether partial liquidation has a lower bracket available. entry and leverage alone are insufficient: the engine needs notional to select MMR, while the remaining live margin determines where the recalculated liq sits after realised loss and fees. a position-size calculation should therefore expose both the starting bracket and the liq left by that size.

for Binance BTC, the relevant checks around this example are concrete:

• confirm whether BTC notional is above the $800,000 boundary and therefore inside the 0.65% third bracket.
• model the reduction required to reach $800,000; from $1,000,000, that reduction is $200,000.
• recalculate the survivor with 0.5% MMR, then account separately for realised PnL, fees and funding accruals.
• treat $93,017 as a bracket-isolation estimate at a $97,400 entry and 20x effective leverage, not as the venue’s final live liq.
• recognise that a BTC position at or below $300,000 is already in the 0.4% first bracket and has no lower tier to enter.

the position-size problem starts with risk, entry and stop rather than the leverage slider. those inputs determine contracts and notional; notional then selects the applicable Binance bracket, MMR and maximum permitted leverage. the liqsiren position-size calculator follows that sequence and reports the estimated liq left by the resulting size using the verified maintenance-margin ladder.

for large BTC positions, the output should be checked on both sides of a bracket boundary. $800,000 uses 0.5% MMR, while a notional above $800,000 enters the 0.65% bracket through $3,000,000. only the first 5 tiers are listed in the calculator data, and larger notionals can have understated MMR when the calculation falls back to the last listed bracket.