Premium concentration and strike ladder
Two panels answer where in the chain the money landed: a strike by expiry heatmap of net directional premium with its three hotspots named, and a strike ladder that stacks call premium left and put premium right around the price.
Senzoukria · Documentation · Updated September 2026
Where to find it
- Where
- Option Flow page (/flow) — concentration in the middle column, ladder in the right column
- Sign convention
- Buying calls and selling puts count positive; buying puts and selling calls negative
- Excluded
- Prints with no aggressor side — counted and reported, never split across directions
- Hotspots
- The three cells with the largest absolute net premium
- Ladder window
- 17 strikes centred on the price
What it does
The concentration panel, titled 'Where the premium is landing', builds a flat heatmap with strikes across and expiries down, coloured by net directional premium on the same diverging scale as the GEX gamma surface. Hovering a cell prints strike, expiry, net premium and the number of prints. The header states the age of the last print — not of the last poll, because an empty feed polled two seconds ago is still forty minutes old — and how many of the window's prints carry an aggressor side.
Two encodings carry the sign, not one: colour, and a 45-degree hatch over the bearish cells, because green and red converge under deuteranopia. A cell with no print at all is drawn as an empty outline, which is a different fact from a cell whose flow balanced out to zero. Below the grid, the three largest cells by absolute net are listed with their swatch, strike, expiry, net premium and print count.
The strike ladder answers the simpler and more frequent question: above or below the price. Call premium grows leftward and put premium rightward from a central strike column, bars scaled to the widest premium in view, with the strike nearest the price highlighted. The header prints the spot used, or says there is no underlying price; the legend totals call and put premium across the rows on screen. No number is written on each row — the panel is there for the silhouette, and the exact figures live in the row tooltip and in the tape.
Settings
| Setting | Default | What it changes |
|---|---|---|
| Input to the heatmap | The prints left by the filter bar | The grid is built after the filters are applied — no implicit filtering of its own |
| Directional sign | Buy call / sell put positive, buy put / sell call negative | The colour and the hatch of every cell |
| Prints without a side | Excluded from the net, counted separately | Shown as 'N/M prints carry an aggressor side · X skipped' in the header |
| Empty cell rendering | Outline only | Distinguishes 'no print here' from 'net zero here' |
| Hotspot list | 3 cells | Which cells are named under the grid |
| Ladder rows | 17 strikes, centred on spot | Which strikes appear; without a price the first rows are kept instead of a centred window |
How to use it
- Read the hotspot list first — three named cells beat a grid of colours for deciding which strike to watch.
- Use the ladder to see whether premium piles above or below price, then switch to the heatmap when you need the expiry that carries it.
- Check the coverage line before trusting the colours: if few prints carry an aggressor side, the net is built on a small sample.
- Hover any cell for the exact net and print count rather than estimating from the colour.
Limits and pitfalls
The sign convention is a market reading, not a fact the exchange publishes: OPRA publishes an execution, not the intent behind it. Legs of a spread priced separately break it, and the panel says so in its footnote.
When none of the prints in the window carries an aggressor side, the heatmap does not guess: it says so and reports how many prints were skipped. When the window holds no trades at all, it says there is nothing to place in the chain.
The ladder keeps a window centred on the price rather than the largest strikes, because a ladder that skips the price cannot be read; strikes outside that window are simply not shown.
Related pages
- Option Flow stats and premium race
- Hedging pressure and sweeps
- Option Flow table and filters
- Gamma walls explained
This page in other languages
Frequently asked questions
- What is the difference between an empty cell and a dark cell?
- An empty outline means no print landed on that strike and expiry. A filled cell near the middle of the scale means prints landed there but the directional premium roughly cancelled out. They are different facts and are drawn differently.
- Why is there a hatch pattern on some cells?
- It marks the bearish side. Colour alone is not enough to separate the two directions for colour-blind readers, so the sign is encoded twice.
- Why does the ladder show only seventeen strikes?
- It keeps a window centred on the price. Beyond it are strikes nobody is watching, and including them flattens the scale so that the strikes near the money stop being readable.