Is Open Interest Live?
And Is It Split Into Buys and Sells?

These are three of the most common questions we get about the data behind the charts, and they deserve precise answers rather than marketing ones. The short version is above. The rest of this article explains where each number actually comes from, how often it changes, and what would have to be true for a buy/sell split to exist at all.

Is open interest live, or is it last night's?

It is last night's, and there is no version of it that is not.

Open interest is not a market data feed in the way a price quote is. It is produced by the clearing house. The OCC consolidates the trade reports from every exchange, which detail all of the opening and closing transactions for the day, reconciles them, and publishes the resulting outstanding contract count. That process runs after the close, and the updated figure becomes available before the next session opens.

So during the trading day, the open interest shown in any options chain — ours, your broker's, anyone's — describes positioning as of yesterday's close. Today's activity does not appear in it until tomorrow morning. This is not a limitation of one data vendor or one platform. The number simply does not exist at any other cadence, because nothing has cleared yet.

What that looks like in the data

Here is a live reading from our own production chain — SPY, same-day expiration, 175 strikes, three requests inside a two-minute window during a regular session:

Open interest: not a single contract of movement. Volume: roughly 41,000 additional contracts in the last fifty seconds. That is exactly the behaviour you should expect, and if you ever see the opposite — an OI column ticking up through the session — it is worth asking what you are really looking at.

Why does another platform show OI changing intraday?

Because it is showing an estimate, and it should say so.

It is possible to model intraday open interest: start from yesterday's settled figure, then add or subtract volume that has been classified as opening or closing. Exchange datasets exist that tag trades that way, so the modelling is not fantasy. But the output is a projection of what OI will probably be tomorrow morning, not the figure the clearing house has published. It can be directionally useful. It will not reconcile with your broker, and it is not the same object.

We show the settled number. When we say open interest, we mean the number that has actually cleared.

Then why do the GEX levels move all day?

This is the part that trips people up, and it is worth being precise about, because it is the difference between a static chart and a live one.

GEX is gamma-weighted open interest. Open interest is the quantity term, and it is fixed for the day. Gamma is the weight, and it is not fixed at all — it is a function of spot price, time to expiry and implied volatility, all three of which move continuously. We recompute gamma for every strike against the live spot price every few seconds, which is why the profile bars, the Call Wall, the Put Wall and the Gamma Flip all shift through the session even though the underlying contract counts have not changed.

Put plainly: the structure is yesterday's, the sensitivity to price is right now. A wall built on 50,000 contracts does not stop mattering because those contracts were opened last week — that is precisely what makes it structural. What changes intraday is how hard dealers have to hedge as price approaches it.

This is covered in more depth in DTE Views Explained, which walks through why Weekly and Monthly levels shift daily even with open interest fixed.

Why open interest has no buy side and no sell side

This one is structural rather than a data-access problem, so it is worth separating from the volume question below.

Open interest counts contracts, not orders. Every open contract has a buyer and a seller at the same moment — someone is long it, someone is short it. A single outstanding contract therefore belongs to both sides simultaneously. There is no coherent way to say that 3,000 of the 5,000 contracts at a strike are "buy open interest", because all 5,000 of them are held long by someone and short by someone else.

The clearing house publishes one outstanding count per strike and expiration. That is the whole object. Any platform showing you "buy OI" and "sell OI" as separate figures is showing you something it has inferred, not something that was reported.

What about volume — can that be split into buys and sells?

Here the honest answer is: yes, in principle, but not with the data we carry, and not for the whole market.

Unlike open interest, a trade genuinely does have a direction. Two kinds of data can recover it:

• Exchange open/close volume datasets. Some exchange groups publish a daily and intraday summary that breaks volume down by participant type, by side (buy or sell) and by position effect (opening or closing). It is real, it is purchasable, and intraday delivery exists. The catch is coverage: each summary only reports the volume that traded on that exchange group's venues. Listed options trade across many exchanges, so a single group's file is a slice of the market, not the consolidated tape.
• Aggressor classification off the full tape. Take every individual trade print, compare it against the prevailing bid and ask, and label it as buyer-initiated or seller-initiated. This gets you the whole market, but it requires the complete real-time trade and quote feed, which is a substantially more expensive tier of data.

We carry neither today. So the volume you see on GEXBoard is the standard consolidated count of contracts traded per strike, split into calls and puts, with no directional label attached — because attaching one without the underlying data would mean publishing a guess with a confident-looking number on it.

We would like to add a directional layer eventually and it stays on the list, but we are not going to attach a date to something that depends on a data contract we have not signed. Our broader data scope, including what we deliberately do not compute and why, is laid out in Why Platforms Show Different GEX Levels.

What you are actually looking at, field by field

Every number on the dashboard and on Chart Lab, with its real source and cadence:

The pattern worth internalising: the quantities are slow and the weights are fast. Open interest changes daily, traded volume accumulates through the session, and gamma reprices continuously. A chart that appears to be moving tick by tick is almost always moving because of the gamma term, not because new positions are being reported in real time.

How to use the two together

Once the cadence is clear, the practical use follows from it.

Open interest answers "where is positioning built?" It is committed, settled and slow. It is the right input for the levels you carry across sessions — the walls you mark on a chart on Sunday night and expect to still be relevant on Wednesday. Its weakness is that it is blind to today.

Volume answers "where is the activity landing today?" It updates through the session and shows you which strikes are attracting attention right now, including strikes that had almost no open interest at the open. Its weakness is that it does not distinguish opening from closing, so a strike being heavily day-traded and a strike where a large new position is being built look similar from the outside.

Neither is a complete picture on its own, which is why we show both rather than picking a side. The most useful reading is the overlap: a strike with heavy settled open interest that is also seeing heavy volume today is structural positioning being actively defended or unwound, and it is a level worth more of your attention than either signal would justify alone. The full comparison of the two methods, with worked examples, is in Volume GEX vs OI GEX.