Gamma Map

Where open option gamma sits for one linked stock, in five views: By strike, Hedging pressure, Net, By expiry and Time drift. A Play forward strip moves every view to a later date. See Reading The Options Suite for how to read it.

At a glance

• An option contract. It gives someone the right to buy or sell a stock at a set price, up to a set date. That set price is called the strike.
• What the pane shows. For one stock, where open call and put contracts are concentrated by strike price. One bar for calls, one bar for puts, at every price level near today's share price.
• Gamma, in two sentences. When the share price moves a dollar, an option's own price moves by some amount. Gamma is how fast that amount itself changes as the share price keeps moving.
• What the bar length is. Not a count of contracts. It is each contract's gamma multiplied by how many of those contracts are open at that strike, put on a dollar scale. That figure is called dollar gamma, and it lets one price level be set beside another.
• The count of contracts. Hover a row and the pane prints how many calls and puts are open at that strike.
• Five views, one pane. Tabs above the chart switch between them. A layout remembers which tab was left open.
• Think of a seating chart. It shows how full each row already is. It does not tell you who wins the show.
• A tall bar. It means a lot of open gamma sits at that price level. It says nothing about where the share price goes next.
• Where the numbers come from. The previous trading day's option chain, which is the full list of option contracts listed on that stock. The figures are counted from that capture. None of them come from our model.
• How fresh they are. You see the latest nightly capture, with nothing held back. The panes built from our model are the ones that carry a delay. This pane is not one of them.
• What it cannot tell you. Who is on either side of those contracts. Open interest, the number of contracts still open, counts contracts and does not name holders. Key difference: By strike shows the two sides apart. Net shows one side minus the other, a counting rule. Neither says who holds the contracts.

The five views

By strike

Two sets of bars drawn back to back, one row per price level. This is the view the pane opens on.

• Rows. The roughly 30 strikes nearest the share price, across the expiry dates chosen in the menu.
• Order. Highest strike at the top, so the chart reads the way a price ladder does.
• Right bar. The dollar gamma carried by open call contracts at that strike.
• Left bar. The same figure for open put contracts.
• Dashed line. Where the share price stood at the nightly capture.
• Net line. A thin line down the middle. It is calls minus puts at each strike, and the chart says so.
• Two arrows. One marks the strike with the most open call gamma, one the strike with the most open put gamma. Each label says where. The net line is a display convention. It is not a claim about who holds the contracts.

Hedging pressure

What a one percent move in the share price would ask of the hedgers who hold the open contracts, by strike.

• The standard assumption. The open calls are treated as held by hedgers. The open puts are treated as sold by them, a convention rather than a claim about who holds them.
• A positive reading. The hedging leans against the move, under that same assumption.
• A negative reading. The hedging leans with the move, under that same assumption.
• The flip strike. The point where the net changes from positive to negative, or back, is named on the chart.
• The call wall and the put wall. The strikes carrying the most net call gamma and the most net put gamma, both named on the map.
• A nightly reading. It restates last night's capture and is not a forecast of what the share price does next.
• Why it is a convention. Open interest counts contracts, not who holds them, so this figure follows a stated rule, never an observed position.

Net

One bar per strike: call gamma minus put gamma.

• A bar to the right. More call gamma is open at that strike than put gamma.
• A bar to the left. More put gamma is open there.
• Two labels. One names the strike where call gamma most exceeds put gamma. The other names the strike where put gamma most exceeds call gamma.
• The same sign markers. Where the net changes sign, the small diamonds appear here too. Subtracting one side from the other is a counting rule. It does not say who holds the contracts.

By expiry

The same open gamma, one row per captured expiry date, nearest at the top.

• Right and left bars. Call gamma and put gamma open on that date, every captured strike added.
• Two lines above the rows. They split the gamma, and the open contracts, into day brackets: the next trading day, the rest of seven days, eight to thirty days, and beyond.
• What the split is a share of. The line says so: the expiries captured, at most ten, out to about seven months. It is never a share of the whole listed chain.
• Not on this view. The expiry menu. This view always shows every captured date.

Time drift

How the deltas of the open contracts drift per calendar day at each strike, in share equivalents.

• What delta is. How much an option's price moves when the share price moves one dollar.
• What drift is. As a day passes, that delta changes on its own, even if the share price stands still. The bar shows the size of that change across the contracts open at the strike.
• Where it comes from. A standard pricing model over last night's quotes, with no interest rate, no dividends, and each strike's quoted volatility held where it is. The pane prints those assumptions.
• One bar, not two. The drift per contract is the same for a call and a put at one strike. Only the number of open contracts differs, so the two sides are added into one bar.
• What it is not. An observed trade. Nobody traded this. It is arithmetic on quotes. Key difference: the gamma views count what is open. Time drift is a computed figure about how that open position's deltas move as days pass.

Play forward

A strip under the tabs moves the pane to a later date. Every options pane that shows the chain moves with it, the way a linked name does.

• The strip. Play, a step back, a step forward, a slider with a tick at each expiry, the date, and a today button.
• Steps. Each step lands on the next expiry. The slider also stops on any day between two expiries.
• At today. The pane shows exactly what it shows without the strip.
• What rolls off. Every expiry on or before the date. Its contracts have expired by then, so they leave every view.
• What stays. Last night's open interest, gamma and prices on the expiries still open. Nothing is priced again.
• The line under the strip. One sentence with the answer at that date. Then the label: projected from today's positions and prices, not a forecast.

What each view does at the date:

• The strike views at the date. By strike, Net and Hedging pressure add up only the expiries still open. The call wall, the put wall and the net move as expiries roll off.
• The gamma flip. Until an expiry has rolled off, it is the nightly builder's list. After that, the same rule runs over the expiries still open.
• The expiry view at the date. On By expiry, the dates that have gone leave the chart. The day brackets count from the date on the strip.
• The drift view at the date. On Time drift, each bar is today's drift per day times the days to the date. It is a convention, not a forecast.
• One expiry at a time. Choose Next expiry in the menu, then step the strip. The chart shows the nearest expiry still open.

Using it for a decision

• Where the walls sit after an expiry. Step to the expiry. The answer names the call wall, the put wall and the gamma flip once it has gone.
• How much disappears this Friday. The answer states the share of open interest left. A big drop means a large share of open contracts expires that day.
• Pin risk around a big expiry. Compare the day before an expiry with the day after it. Walls that vanish after it were held up by that one date.
• Choosing an expiry. An expiry that holds most of the gamma near the share price carries the most hedging around it until it expires.

The expiry menu

One menu above the chart picks which captured expiries By strike, Net and Time drift add together.

• All expiries. Every date the capture holds. This is the starting choice.
• Next expiry. The nearest date only.
• Within 7 days. Every date inside seven calendar days.
• One date. Any single captured expiry, listed with how far away it is. There is no same day choice. The capture is taken after the close, and the contracts that expired that day are gone from it.

The sign markers

Small diamonds on the centre line mark where the net changes sign. The label reads net gamma changes sign near K · calls minus puts, a convention, with the price level in place of K.

• Who works them out. The nightly builder, once, for every name. At today the pane draws the list it is served.
• After the strip rolls an expiry off. The builder has no list for a later date, so the pane runs the same rule over the expiries still open.
• The rule. The thirty strikes nearest the share price, across every captured expiry. A crossing between two strikes is placed by a straight line between them. A crossing is dropped when the larger of its two strikes carries under four percent of the largest net.
• All of them. When the net crosses zero more than once, every crossing is shown. Picking one would be a claim.
• Only on All expiries. Under any other menu choice no marker is drawn, and the note under the chart says so. The rule runs over every captured expiry, so it cannot describe a smaller ladder. The marker sits between two strikes, so the number it prints is usually not a listed strike. It is arithmetic about the two bars, and nothing more.

The numbers on screen

Hover a row and the exact figures for that strike appear.

Implied volatility. It is a yearly figure that the contracts' own prices imply under a standard pricing model. The pane prints it as a percentage with one decimal place. It is not a statement that the share price will move that much. The header. A small label at the top gives the open call and put counts for the whole stock.

The numbers under the picture

Added 2026-09-16. A row of figures under the chart restates without a hover. It sits on every view but Hedging pressure, which already carries its own numbers strip across the top:

• Calls open, puts open. The open contract counts for the whole stock, the same two the header states.
• Net gamma, total gamma. The whole-name dollar gamma for a one percent move, calls minus puts and the two sides added. On By strike and Net it also names the call wall, the put wall and the nearest gamma flip, when the ladder carries one.
• Call gamma share. Still only on Options Snapshot, which is the one place that third whole-name figure lives.

What hedging does near a wall, in general

This section is education about how option hedging works under the standard assumption. It describes a mechanism, not this name's next move.

• Why a wall matters at all. A wall is the strike where the most net gamma is open. Gamma is how fast an option's delta changes as the share price moves. Whoever hedges those contracts trades shares to stay hedged. The shares they trade per one percent move is the figure on the Hedging pressure tab.
• Nearing a call wall from below. Under the standard assumption the hedgers are long the calls. Long gamma hedging leans against the move. As the price rises toward the strike they sell shares, and as it dips they buy them back. In general that damps the moves near the strike. That is why traders speak of a call wall as a place where a rally tends to slow.
• Gamma is largest at the money. A contract's gamma peaks when the share price sits at its strike and fades as the price moves away. So the hedging above grows as the price nears the wall and shrinks once the price is well past it.
• Nearing a put wall from above. Under the same assumption the hedgers are short the puts. Short gamma hedging leans with the move. As the price falls toward the strike they sell shares, and as it bounces they buy. In general that adds to the moves near the strike rather than damping them.
• What happens to the wall itself. A wall is open interest, and open interest changes when contracts are opened, closed, rolled or expire. The nightly capture shows where it sat at the close. Since Yesterday shows how it moved overnight, and Expiry Ladder shows how much of it falls off at each date. A wall the price has passed through often stops being a wall in the next capture, because the contracts behind it are closed or rolled.
• Past the flip strike. Where the net changes sign, the hedging changes from leaning against the move to leaning with it, under the assumption. Traders read a price crossing the flip as a change in how the name tends to trade. Calmer on the positive side, jumpier on the negative side.
• What the desk does not say. It does not say where this name's price goes, whether a wall holds, or what the price does tomorrow. The mechanism above is textbook option hedging under a stated assumption. The reading is last night's count.

Reading it well

1. A big bar is a concentration of open gamma. A strike carrying a lot of gamma is where a lot of option exposure is open. It is not a price level. It says nothing about where the share price goes next.
2. Where the wall and flip words point. This pane names the call wall, the put wall and the gamma flip strike wherever they sit. The Hedging pressure tab gathers them under one header, computed under the standard assumption and labelled that way. A record of open contracts still shows no price effect, so none of them is a level the price must respect.
3. Keep calls and puts apart in your head. They are drawn as two bars on By strike for a reason. Whether market makers are net long or short the open contracts cannot be seen from open interest. So the Net view and the net line are only a sign convention. Read the Hedging pressure tab for that reading, built under the standard assumption and labelled as one.
4. Use the sign markers to find your place, not as a level. They show where the calls minus puts arithmetic crosses zero. That helps in a dense row of bars. They are not a support or resistance line.
5. Read Time drift as a model figure. The pane prints its assumptions. Change any of them and the bars change. Nothing on that view was observed.
6. This is the near-the-money view only. Roughly 30 strikes nearest the share price. For the full nightly count, strike by strike and expiry by expiry, see Strike Table. For how the same figures have moved across recent trading days, see Positioning Replay.

Common misreadings

• "The big bar is a wall, ceiling or floor the price will not cross." The bar names a concentration of open gamma. It is not a price limit. See Hedging pressure for the same strikes, named as a call wall or a put wall, always beside the arithmetic behind them.
• "The Net view shows what dealers are doing." It shows calls minus puts, a counting convention. Hedging pressure states the same net under the standard assumption and names it plainly.
• "The sign marker is a level." No. It is where two bars' arithmetic crosses zero, placed by a straight line between two strikes.
• "Time drift shows trading." No. It is a computed figure from quotes. Nobody traded it.
• "This is the whole options book for the stock." No. It is the strikes nearest the share price, in at most ten expiries. Open interest can and does sit further out. Everything on this pane is market data from the previous trading day's option chain, or arithmetic on it that says so. Nothing here is a forecast. The model portfolio we publish does not hold options on single stocks.

Frequently asked questions

Does a tall bar mean the share price will stop or turn there? Not by itself. It means a lot of gamma is open at that strike right now. The section What hedging does near a wall explains the mechanism traders have in mind. The desk does not forecast whether it plays out for this name. What happens when the price gets closer to a wall? Read What hedging does near a wall, above. In short: under the standard assumption, hedging near a call wall leans against the move and near a put wall leans with it. It grows as the price nears the strike. The wall itself is open interest and can move, shrink or vanish in the next capture. Ask the desk to explain the hedging near the wall on your screen and it walks through the figures shown. What is the difference between By strike and Net? By strike draws call gamma and put gamma as two bars. Net draws one bar, calls minus puts. The second is a counting rule and hides which side is bigger only by its direction. What is the thin line down the middle on By strike? It is the net line: calls minus puts at each strike. It is a display convention, not evidence of who holds anything. Where it crosses zero, a marker labels the price level it crosses near. Can I tell what market makers or dealers are doing? Open the Hedging pressure tab. It computes the net under the standard assumption, calls held by hedgers and puts sold by them, and states that assumption on the chart. Open interest still cannot show who is actually long or short, so the figure stays a labelled convention, not an observed position. It never promises the price stops or turns at a strike. Why do the sign markers disappear when I pick an expiry? The nightly builder works them out over every captured expiry. A ladder over fewer expiries is a different ladder, so the pane draws no marker for it rather than a wrong one. Why do I only see strikes close to the share price? The pane shows the roughly 30 nearest strikes. For the full nightly count across every strike and expiry, see Strike Table. Can I use this pane to time a trade? No. It restates option positions that already existed in the previous trading day's data. Is there a vanna view? No. Under the model the pane uses, vanna and the drift per day are the same shape within one expiry, so one view carries it. Time drift is that view. Where are net gamma and total gamma for the whole name? On Options Snapshot, as three tiles. The Options Screener carries them for every name.

Related panes

• Reading The Options Suite is the shared primer. It covers the vocabulary and what the data covers. It also carries the compliance rules every options pane follows.
• Options Snapshot carries the whole-name gamma figures on tiles.
• Strike Table is the full nightly count of open interest and gamma, strike by strike and expiry by expiry.
• Expiry Ladder shows the same open contracts organised by expiry date, restated as shares.
• Positioning Replay plays back how this stock's open contracts have shifted across recent trading days.