A tour of the screen
The Big OI Movement Radar names the symbol, expiry and the filter in use: an adaptive OI change filter that keeps the major increases and decreases at each timestamp rather than applying one fixed threshold, so quiet and busy buckets are both represented.
- Controls. Choose the symbol, expiry and historical date in Filter Options, with live updates (about every 20 seconds) and a backtest mode for historical expiries. A timeframe switch offers 5, 15, 30 or 60 minutes, and you can set how many rows to show per page.
- Summary cards. Contracts scanned, the net OI change on the call side and on the put side, and the largest single print.
- Replay timeline. Play back the session snapshot by snapshot, or drag the cursor to a time.
- Interval OI Flow. A bar chart of the last several buckets split into CE buildup, CE unwind, PE buildup and PE unwind.
- Call and put tables. Separate tables list each print with its interval and spot, the strike with its moneyness (ATM, ITM or OTM), the close, the change in the option's price, the change in open interest and an interpretation tag.
An interpretation colour legend sits above the tables: fresh bullish, bullish cover, fresh bearish and bearish unwind. The colour shows what the print means for the underlying, so call short covering and put long unwinding share one colour, while call long unwinding and put short covering share another.
The four classifications
| Option price | Open interest | Label | Common reading |
|---|---|---|---|
| Rising | Rising | Long buildup | New positions added while the premium rose. Often buying, but writing or hedging into a rising premium can look the same. |
| Falling | Rising | Short buildup | New positions added while the premium fell. Often writing, but falling implied volatility and decay can produce it too. |
| Rising | Falling | Short covering | Positions closed while the premium rose, consistent with writers buying back. |
| Falling | Falling | Long unwinding | Positions closed while the premium fell, consistent with buyers exiting. |
These labels describe patterns in one contract's premium and open interest. They do not identify who initiated the trade, and a falling put premium is not inherently bearish for the underlying. Always read the call and put sides together.
How to read it
- Set the symbol, expiry and timeframe. A single short bucket can be noise; a 15 or 30-minute burst more often reflects deliberate positioning.
- Check the summary cards, then find the largest print and note its strike, moneyness and distance from spot.
- Scan the biggest changes near the money and one to three strikes away, where index option flow is usually most actionable.
- Read the call and put tables together. Call short buildup with put short covering tells a cleaner story than either alone.
- Replay the timeline to see whether the activity is a one-bucket burst or a sustained build, and whether the largest change is migrating from one strike to another.
Limits
The largest print is a clue, not a signal. Far out-of-the-money strikes can rank highly during event sessions because writers and speculators crowd them, and those spikes usually need confirmation from near-the-money structure. OI change alone is incomplete: it needs price change and strike context. A strike can also reappear several times in a session if participation keeps returning to it.
For the same bucket-to-bucket comparison arranged as four quadrants by price and OI direction, see the OI Spurts guide. To follow strikes through the day, use Trending OI.