Why does a BloFin BTC limit order sit "pending" and then disappear after 10 minutes?

What the rule does

BloFin checks every order price against a band built from the Index Price, which is a weighted average of prices from major exchanges for that pair. An order priced outside the band does not execute immediately. It can wait in the book for up to 10 minutes while the system keeps trying to fill it if the market comes back inside the band. If it still cannot fill inside the band after 10 minutes, it is canceled automatically.

The band is not the same for every contract. The parameters sit on each contract's information page, and BloFin can adjust them without a separate announcement.

The BTCUSDT formula

For roughly the first 10 minutes after a contract is generated, the BTCUSDT band is plain: buys can go up to Index x 1.02 and sells down to Index x 0.98.

After that, the standing rule adds the recent premium:

• Buy ceiling = Min[ Max(Index, Index x 1.01 + average premium over the last 2 minutes), Index x 1.02 ]
• Sell floor = Max[ Min(Index, Index x 0.99 + average premium over the last 2 minutes), Index x 0.98 ]

There is also an outer limit on the far side: a buy price cannot be set below Index x 0.2, and a sell price cannot be set above Index x 5.

Worked steps with the live index (Nov 4, 3:56 PM ET)

BloFin's public feed showed BTC-USDT index 80,057.7 and mark 80,020.5. The 2-minute average premium is not published in the feed, so the mark minus index gap of -37.2 is used here as the stand-in.

1. Index x 1.01 = 80,858.28. Add the -37.2 premium: 80,821.08.
2. Compare with the Index (80,057.7). The larger one is 80,821.08.
3. Cap at Index x 1.02 = 81,658.85. The smaller one wins, so the buy ceiling is about 80,821.1, which is 763.4 above the index (0.95%).
4. Sell side: Index x 0.99 = 79,257.12, plus -37.2 = 79,219.92. Floor at Index x 0.98 = 78,456.55. The larger one wins, so the sell floor is about 79,219.9, which is 837.8 below the index (1.05%).

Now the opening scenario. The BloFin 24h low for BTC-USDT was 75,688.7, which is 4,369 below that index (5.46%). A sell limit parked at the 24h low to "make sure it fills" sits far below the 79,219.9 floor. That order is exactly the one that waits and then gets canceled.

Same rule, different coin

DOGEUSDT uses wider numbers: 4% for the first 10 minutes, then Index x 1.04 plus premium, capped at 15%. With the DOGE-USDT index at 0.07663 and mark at 0.07662, the ceiling works out near 0.07968 and the floor near 0.07355, a band of about 4% each way instead of about 1% on BTC.

So do not assume ETH, SOL or XRP use the BTC settings. Their 24h ranges on BloFin today were 2,225.04 to 2,448.87 for ETH-USDT, 89.85 to 98.17 for SOL-USDT and 1.2427 to 1.3416 for XRP-USDT. Each one has its own line on its contract page.

Common mistakes

• Using a far-away limit as a "guaranteed fill". If the price is outside the band, it is the opposite of guaranteed.
• Reading the last price instead of the index. The band is built from the Index Price, so check the index line on the order panel first.
• Copying one contract's band to another. BTC and DOGE are already roughly 1% vs 4% apart.
• Forgetting the 10-minute clock. If you walk away, you may come back to a canceled order and an open position.

Short FAQ

Q: Why was my order not rejected at once? A: Orders that trigger the rule can wait up to 10 minutes in case the market returns inside the band.

Q: Will it fill on its own if price comes back? A: Yes, if the market returns inside the permitted range during the wait, it can execute normally.

Q: How do I avoid it? A: Check the index, keep your price inside the range shown on the trading interface, and resubmit if needed.

Rule of thumb: on BTC, anything more than about 1% through the index is likely to wait; on DOGE, about 4%.