How risk limits work on BYDFi: MMR 100% trigger and size-driven tiers

Risk limit tiers exist, but the public FAQ marks its sample tier table as not live, so this guide quotes the rules and formulas and leaves every numeric tier cutover to the live Risk Limits list. That is the disciplined way to teach the feature without inventing digits.

Rule: when maintenance margin rate (MMR) reaches or exceeds 100%, the system triggers liquidation. MMR rises as position size rises because more margin must be reserved. Changing selected leverage does not directly change MMR.

Formulas and rules

Liquidation trigger: MMR >= 100%. MMR here is the venue's risk indicator for the position and account exposure as described in the FAQ. Monitor MMR as size and equity move. Size rule: as position size increases, more margin is reserved and the corresponding maintenance margin rate increases. Leverage rule: MMR follows the position's size path, not the selected leverage multiplier. Changing leverage does not directly rewrite MMR. Tiered liquidation: when liquidation starts, the engine follows a tiered process based on the position risk limit so it can avoid wiping the entire position in one step when the rules allow a reduction first.

Numeric tier caps, max size per tier, and example high-leverage rows that appear in illustration tables are out of scope for this package. Confirm those on the live Risk Limits list for each pair.

Worked steps

1. Before you size a $BTC.USDT, $ETH.USDT, $SOL.USDT, $XRP.USDT, or $DOGE.USDT perp, open the Risk Limits list for that pair.
2. Note the size tier that would apply to your planned notional. Do not copy illustration numbers from help pages.
3. Watch MMR as a live percentage. The FAQ's trigger line is 100%.
4. If you plan to add size, ask whether the add crosses a higher risk-limit tier. Size is what walks you up the reservation schedule.
5. If you only lower leverage and leave size unchanged, do not expect MMR to fall just because the slider moved.
6. If MMR is climbing toward 100%, the FAQ's path is tiered liquidation by risk limit, not a single mystery candle on last price.
7. After any reduce-only close, re-read MMR and the active tier. A partial close can drop you into a lower reservation row; confirm it on the panel instead of assuming.
8. Keep cross versus isolated in view. The shared equity pool versus a single-position bag changes how fast MMR can race to 100% on the same mark move.

What changes it

• Position size: primary driver of the maintenance reservation and tier.
• Risk limit tier: governs how tiered liquidation reduces exposure.
• Margin mode and equity: cross versus isolated changes which balances back the position.
• Mark path: liquidation handling is a risk process on the venue's risk indicators, not a last-price beauty contest.
• Sample help-page tier tables: useful for learning the shape of a ladder, useless as a source of live numbers.

Common mistakes

1. Reading an illustration tier table in a FAQ and treating those figures as the live ladder.
2. Cutting leverage and assuming MMR improved while size stayed put.
3. Waiting for last price to look safe while MMR is already near 100%.
4. Skipping the Risk Limits list after a large winner's add. Size is still size.

FAQ

Q: Can we quote a BYDFi max leverage from the FAQ alone? A: Not from the sample help-page table. Use the live Risk Limits list and the pair's trading panel.

Q: Does MMR = 100% mean the whole position is gone instantly? A: The FAQ describes a tiered liquidation process based on the position risk limit, aiming to avoid liquidating everything immediately when a partial reduction can clear the risk.

Q: Is changing leverage a risk-limit change? A: Leverage changes buying power. The FAQ says it does not directly change MMR; size does.

Q: Why avoid sample dollar sizes here? A: Because the FAQ itself labels its tier figures as samples, not the live list. Live list first, then math.

Keep size small while the book is thin.