Level 2: Limit Orders, Never Stops
Level 2 is a display of resting limit orders at each price level away from the current quote. It shows only limit orders, never stop orders, and on fragmented equity markets it shows one venue's book rather than the whole market.
How it works
Level 1 is the best bid and best offer. Level 2 adds the prices behind them and the size resting at each — a few levels deep on each side, sometimes more.
The reason to look at it is size distribution. A thick book absorbs orders without moving much; a thin one moves several ticks on a modest trade. That is a real, current property of the market and it is not visible on any chart.
The three things it does not show
Stop orders are not in it. They are held at the broker and released as market orders when triggered, so they never rest in any book. Every claim about “seeing where the stops are” is therefore an inference from chart shape, which the liquidity pool page treats directly.
Hidden size is not in it either. An iceberg order displays a small slice and refills silently as it trades, so a level showing 200 can absorb 20,000. Displayed size is a lower bound.
And on equities it is fragmented. A stock trades across many exchanges and alternative venues, plus dark pools which display nothing at all. A single venue’s Level 2 is a slice of the market, not a census of it.
Futures are the clean case, because one contract trades on one exchange and the book is complete — which is why depth of market is a futures trader’s tool and Level 2 is an equity trader’s approximation.
In practice
Most displayed size never trades. Orders are posted and pulled continuously by automated systems operating far faster than a human can react. A wall of size at the next price is a statement of current intent, and intent is revocable.
Which is the key practical caution: the book is a snapshot of what people are currently willing to do, not a schedule of what will happen. Reading it as a forecast is reading a queue as a commitment.
Time and sales — what actually traded — is the more reliable companion display. Executions cannot be cancelled. Order flow analysis is built on that record rather than on the book, for exactly this reason.
None of it is relevant to a longer-horizon decision. The book at any instant says nothing about the next week, and the information decays in seconds.
Outside regular hours the book is nearly empty, so the display looks alarming and means little. The same is true in the first seconds after an opening gap, when spreads are widest and depth is thinnest.
Your own stop is invisible here too, which is worth knowing if you have ever worried about it being seen.
The spread the display shows is the visible half of the round-trip cost, which on this site’s shared history is 2% of a median bar’s range.
On a thin instrument a single order rearranges the whole display, which makes any pattern read from it a pattern in one participant’s behaviour.
What Level 2 is not
It is not the whole market. On equities it is one venue among many, plus venues that display nothing.
It is not a map of stops. Stops are not orders in a book.
It is not a forecast. Displayed size can vanish before you act.
And it is not the same as order flow. That is built from executions; this is built from intentions.
When it fails
In a range the book looks balanced almost all the time. Size sits on both sides, the imbalance flickers back and forth, and there is nothing to read that is not noise.
The second failure is trusting a wall. Large displayed size at a price is the most common thing traders act on and the least reliable, because it is also the easiest thing to post and pull.
A third is reading it on a fragmented market. Equity Level 2 from one venue can look one-sided while the consolidated market is balanced.
A fourth is the attention cost. A fast-updating ladder consumes concentration continuously, and for anyone not trading in seconds that attention is better spent elsewhere.
And a fifth is treating displayed size as a count of participants. One large order and many small ones look identical, and hidden size makes the total a floor rather than a total.
The original data
On this site’s shared 576-bar history the round-trip cost is 0.0098 price units — 2% of the median bar
range of 0.493 and 45% of the smallest bar of 0.022 — and bar ranges span 0.17 to 1.10 between the tenth
and ninetieth percentiles. The figures are in research/series-measurements.json, produced by
site/measure_series.py.
The reason those cost figures belong on a page about a depth display is that they set what depth reading is for. If your round trip is 45% of a quiet bar, no amount of book reading makes a quiet bar tradeable — the cost has already consumed the opportunity. Level 2 earns its subscription only where your edge is in execution rather than in direction, and that is a narrow set of situations that most people paying for it are not actually in. Work out your cost as a share of your typical target first; the answer decides whether the display is a tool or a distraction.
Related
Order book covers what a book is and what reading one can and cannot support. Depth of market is the futures version, where the book is complete. And order flow is the analysis built on executions rather than intentions.
Level 2 was the first thing I paid for and the first thing I cancelled. Watching size appear and disappear taught me something genuinely useful about how little of a displayed book is real, and then it stopped teaching me anything and started costing me attention.
— Michael Whitman
This page is educational, not financial advice. Test every idea on your own charts before risking money.