Iceberg orders
An iceberg shows only a chunk of a limit order on the book at a time and tops it up as it fills, until your whole size has traded. Use it to work a large order without showing its full size.
On this page: How it works
Iceberg runs in your browser, in Mirrorlane. The exchange sees only the orders it places, never the size behind them. It keeps going while any Mirrorlane tab is open on this device, and picks up again when you reopen Mirrorlane here.
How it works
Section titled “How it works”The iceberg places a limit order for one chunk. Once at least a tenth of the chunk has filled, it adds a new order that brings what rests back up to the chunk, beside the earlier ones, so those keep their place in the queue. What rests stays at about one chunk, over at most 10 orders. It looks again every 5 seconds.
Where each order rests depends on Post only:
- With Post only, on by default, a buy rests at the best bid but never above your price, and a sell at the best ask but never below it. When a better bid or ask appears ahead of an order, the order moves up to it, still never past your price. The exchange cancels a post-only order that would fill at once, so these orders fill only as a maker.
- Without Post only, every order rests at your price. If that price crosses the book, each order fills at once as a taker, and the iceberg keeps placing them at your price.
Near the end it leaves no sliver: when the part left after an order would be too small to place on its own, that order takes it too. A last remainder below the market’s minimum, with nothing resting, goes as a market order, filling no further than 3% past the best price on the other side. Every order expires 1 hour after it is placed, and while the iceberg runs, the next top-up replaces it.
Settings
Section titled “Settings”| Setting | What it does |
|---|---|
| Price | Your limit: the most a buy pays, the least a sell takes. On the market’s tick. |
| Total size | All of it. |
| Chunk | How much shows at a time, in the asset. At most 33.33% of the total size, and at least the market’s minimum size at your price. It has no default. |
| Post only | On by default. See above. |
| Reduce only | Off by default. Orders only make your position smaller, and the iceberg ends once there is nothing left to reduce. |
The order details show Refills (the total size divided by the chunk, rounded up), Order value, the margin and Fees. With Post only off, the ticket warns that orders crossing the book fill as a taker.
Before you start
Section titled “Before you start”- Remember me, in Settings, Security, must be on, so strategies pick up after a reload. With a key already in use, refresh this device’s key after turning it on. See Your trading key.
- Advanced order types, in Settings, Trading, shows Iceberg in the Advanced menu. It is on by default.
- Up to 10 strategies run at once on one account: Chase Limit, Iceberg and Advanced TWAP together.
- Plus or Premium. On a Standard account, trading here is paused. See Account types.
Each order is an ordinary limit order and pays that order’s fee; a last remainder sent at market pays a market order’s. The Fees row shows an estimate before you start. See The fee.
When it stops
Section titled “When it stops”- You close the last Mirrorlane tab. Its orders stay on the book until they fill or expire, within the hour. Reopen Mirrorlane here and the iceberg resumes with those orders.
- The connection to the exchange drops. Every running strategy stops (Aborted: Disconnected) and cancels its orders. It doesn’t restart on its own.
- You sign out, or revoke this device’s key. Strategies stop and cancel their orders first. While your wallet registers a new key, they place nothing.
- An order’s outcome is unknown. If the exchange doesn’t answer, the iceberg places nothing while it looks for that order, for up to two minutes (Waiting for an order to confirm). Found, it carries on. Never found, it stops, and the order is watched until it would have expired: cancelled if it rests, its fills counted. No order is ever sent twice.
What can go wrong
Section titled “What can go wrong”- The price moves away from your limit. Nothing fills past your price, so the iceberg waits, for as long as you leave it running.
- An order is refused. The iceberg tries again every 5 seconds and shows the reason under its status. If the reason won’t clear, such as not enough margin, stop it.
- You cancel one of its orders by hand. The iceberg tops up again at its next look. To end it, stop it.
- Several strategies run at once. They share one request budget, and the terminal paces orders to stay inside the exchange’s limits, so top-ups can lag.
- An older tab holds the strategies. After a release, an older Mirrorlane tab can keep them, and a new iceberg won’t start. Close older tabs, then refresh.
Follow or stop it
Section titled “Follow or stop it”The Strategies tab, beside Open orders, shows each run: how much has filled, the average price, the share filled as a maker, its status and the seconds to its next look. Stop ends it: what has filled stays filled and its orders are cancelled. Stop all ends every run. Its orders show in Open orders marked by a strategy, where Edit is off. A notice says when a run completes or stops.
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