What is a SuperDOM?
The depth of market ladder, column by column. What the columns mean, how to read it, how Level 2 differs from market by order, and what the ladder can't tell you.
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A SuperDOM is a depth of market ladder
A SuperDOM is a depth of market ladder: a vertical list of prices with the resting buy orders on one side and the resting sell orders on the other. It shows how much size is waiting at each price right now. You'll also hear it called a DOM, a price ladder or a depth ladder. They're all the same thing.
DOM stands for depth of market. "SuperDOM" is what some trading platforms call their ladder, and traders now use the name for ladders in general.
How do you read a depth of market ladder?
Start in the middle. The price column runs down the centre, with bids at and below the market and asks at and above it.
- Price column. One row per tick, higher prices at the top.
- Bid size. How many contracts or shares buyers have resting at that price. These are limit orders waiting to be filled.
- Ask size. The same thing for sellers.
- Best bid and best ask. The highest bid and the lowest ask. Together they're the inside market, and the gap between them is the spread.
- Last trade. Many ladders mark the last traded price and show the volume traded at each price.
Every number on a ladder is an intention. Nothing has traded yet. A trade happens when someone sends a market order, or a limit order that crosses the spread, and takes some of that resting size.
What do traders look for on the ladder?
They look for size that's unusual, and for what that size does when price gets close to it.
Large resting orders
A price with much more size than its neighbours. It may slow price down. It may also be gone before price gets there.
Pulling and stacking
Size cancelled as price approaches is being pulled, and size added is being stacked. Watch the change. It says more than the number itself.
Absorption
Trades keep hitting a price, the size there keeps getting refilled, and price doesn't move. Someone is taking the other side.
What is the difference between Level 2 and market by order?
Level 2 gives you one total per price. Market by order gives you every single order at that price, in queue order.
On Level 2, one order for 200 contracts and two hundred orders for 1 contract look identical: 200. On market by order data, usually shortened to MBO, they look nothing alike. And it matters, because one large order can be cancelled in an instant, while two hundred small ones rarely leave together.
| Data type | What you see | What you can't see |
|---|---|---|
| Level 1 | Best bid, best ask and last trade | Any size behind the inside market |
| Level 2 (market by price) | Total size at each price, several levels deep | How many orders make up the total, and their place in the queue |
| Market by order (MBO) | Each order at each price, with its size and queue position | Hidden size and the intent behind an order |
MBO data is also how you spot iceberg orders. An iceberg shows a small size and refills every time that size trades. On Level 2 the price just seems to hold. On MBO data you can see the refills, as new orders arriving at the same price.
You won't get MBO everywhere. It depends on the exchange, the data provider and the instrument. Some futures feeds carry it. Spot forex has no central order book at all, so a forex ladder only shows the book of one broker or venue.
What can the ladder not tell you?
It can't tell you whether an order will still be there when price arrives, and it has no memory of what was there before.
- Orders get cancelled. Most resting orders never trade. Showing size to move other traders and then pulling it is called spoofing. It's illegal in regulated markets and it still happens.
- Not all liquidity is displayed. Icebergs show part of their size. Stop orders, and orders traders are holding back, aren't in the book at all.
- It shows this instant only. A ladder can't show you that a level has been defended all morning. A liquidity heatmap plots the same book over time and fills that gap.
- It doesn't show who traded. The ladder shows resting orders. For executed volume at each price you need Times and Sales or a footprint chart.
- It's fast. In a busy market the numbers change many times a second. Reading a ladder takes screen time, and a number that looks important is often noise.
A ladder is for timing around a level you already have a reason to trade. It isn't a signal on its own, and reading it doesn't remove the risk of the trade.
How does the SabrTrader SuperDOM show the book?
It docks as a panel on the right edge of the chart, aligned to the price axis, so the size at a price sits level with that price on the candles.
There are two modes. Classic mode is the aggregated Level 2 view and works on any depth feed. MBO mode shows the individual orders at each price, and adds iceberg detection and highlighting of aggressive limit orders. MBO depends on your provider and instrument: Rithmic and Databento carry it on many contracts. When it isn't available, the ladder runs in classic mode.
The full feature list is on the SuperDOM page. It's part of the paid order flow suite.
Read the book next to your chart
Every paid feature is open for the first 14 days, the SuperDOM included. Connect a depth feed and add it to a chart.
Download SabrTrader free Compare plansMarket data comes from your own provider.
Questions about the SuperDOM
Is a SuperDOM the same as a DOM?
In practice, yes. DOM means depth of market, and SuperDOM is a product name for a DOM ladder that turned into a general term. Price ladder and depth ladder mean the same thing.
What is the difference between Level 2 and a DOM?
Level 2 is the data, the DOM is the display. Level 2 data holds the total size at each price, and a DOM ladder shows that data in a vertical, price-aligned layout.
What does market by order mean?
Market by order, or MBO, is depth data that lists every individual order at each price. You see the number of orders, the size of each and their place in the queue, where Level 2 only gives you the total.
Does the DOM show all orders in the market?
No, only displayed limit orders. You can't see the hidden part of iceberg orders, stop orders, or orders that haven't been sent yet.
Can large orders on the DOM be fake?
Yes. An order can be placed to be seen and then cancelled before it trades. That's why traders watch whether size stays and refills when price reaches it, and don't rely on the number alone.
Do I need market by order data to use a DOM?
No, a DOM works on ordinary Level 2 depth. What MBO data adds is the per-order view, which helps with queue reading and iceberg detection.
What is the difference between a DOM and a heatmap?
A DOM is the order book at this moment. A heatmap is the same book over time, so you can see where size built up, stayed and was pulled. Many traders use both.