0.04%: how far ETH can move against a 500x long on BYDFi before maintenance margin and the closing fee take it

Where that number comes from. At 500x the initial margin is 0.2% of the position. BYDFi's first ETH tier keeps 0.1% back as maintenance margin, and liquidation also has to cover a closing fee at the 0.06% liquidation fee rate. 0.2% - 0.1% - 0.06% leaves 0.04%. BYDFi's own rule: an isolated position is liquidated when (maintenance margin + closing fee) / (position margin + unrealized PnL) reaches 100%.

The image is BYDFi's live ETHUSDT perpetual page at about 10:20 AM ET: last 2,329.72, -0.69%, index 2,330.89, fair 2,329.80, funding +0.0065% with the countdown, 24h high 2,386.33 and low 2,314.43, open interest 380.622M, the 15m chart and the order book. Next to the Chart tab sits the Risk Limit tab, which holds the full tier table for the pair.

1 ETH long (100 contracts of 0.01 ETH), fair price 2,329.52 from the public API at 10:19 AM ET, assumed to be in tier 1, fees at 0.06%:

Leverage | Margin | Room before liquidation | Approx liq price

• 500x | 4.66 USDT | 0.93 USDT (0.04%) | 2,328.59
• 100x | 23.30 USDT | 19.57 USDT (0.84%) | 2,309.95
• 20x | 116.48 USDT | 112.75 USDT (4.84%) | 2,216.77

In each row the room is margin - 2.33 maintenance - 1.40 closing fee. Funding is ignored. It is 0.0065% right now, about 0.15 USDT per ETH per settlement.

BYDFi ETH tier ladder (maintenance / initial / max leverage)

• Tier 1 | 0.1% | 0.2% | 500x
• Tier 2 | 0.25% | 0.5% | 200x
• Tier 3 | 0.4% | 0.8% | 125x
• Tier 4 | 0.5% | 1% | 100x
• Tier 5 | 0.665% | 1.333% | 75x
• Tier 6 | 1% | 2% | 50x
• Tier 7 | 2% | 4% | 25x
• Tier 8 | 2.5% | 5% | 20x

The pattern: the initial rate is double the maintenance rate in every tier. Tiers are set by position value, so a bigger ETH position cannot keep 500x. Picking lower leverage does not lower the maintenance rate, it only adds margin above it.

For scale, ETH's 24h low of 2,314.43 was 0.65% under the fair price, already more than the room at 500x. BTC, SOL, XRP and DOGE have their own tables in the same tab.

Checklist before choosing leverage on BYDFi

• Read the Risk Limit tab for your pair and find the tier your size falls in
• Subtract maintenance rate and liquidation fee rate from the initial rate to get your real room
• Compare that room with the 24h range
• Pick isolated if you want the loss capped at the position margin. Cross is the default, and every cross position closes together when one is liquidated
• Switch modes before opening: BYDFi will not switch with an open position or limit order

Worked steps behind each row of the table:

1. Notional: 100 contracts x 0.01 ETH x 2,329.52 is about 2,329.52 USDT.
2. Margin: notional divided by leverage, 4.66 USDT at 500x.
3. Maintenance: 0.1% in tier 1, about 2.33 USDT.
4. Closing fee: 0.06%, about 1.40 USDT.
5. Room: margin minus maintenance minus closing fee. Divide by 1 ETH and subtract from the fair price for the approximate liquidation price.

Common mistakes:

• Reading 500x as "500 times the profit" and forgetting it also means about 0.04% of room. A normal minute of ETH movement can cover that.
• Counting only the opening fee. The liquidation fee is part of the line, so it eats room before price moves at all.
• Assuming a bigger position keeps the same tier. Size moves you down the ladder, from 500x in tier 1 to 20x by tier 8.
• Opening in cross by default without noticing. Cross is the default on BYDFi, and every cross position closes together when one is liquidated.
• Trying to switch modes with a limit order still resting. BYDFi will not switch until it is gone.

Short FAQ

• Why is the initial rate double the maintenance rate? That is how BYDFi's ETH ladder is set in every tier shown.
• Does funding matter at 500x? At 0.0065% it is about 0.15 USDT per ETH per settlement, which is a real share of 0.93 USDT of room.
• Where do I see my tier? In the Risk Limit tab next to the Chart tab.