Why open interest matters
Price tells you what happened; open interest tells you whether positions were opened or closed to make it happen. Rising OI means new money is entering; falling OI means traders are exiting.
The four quadrants
| Price | OI | Reading | What it suggests |
|---|---|---|---|
| Up | Up | Long buildup | Fresh buying — trend has conviction |
| Down | Up | Short buildup | Fresh selling — bears are adding |
| Up | Down | Short covering | Shorts exiting — rally may lack follow-through |
| Down | Down | Long unwinding | Longs booking out — weakness without new shorts |
Using it well
- Look for buildup that persists over several sessions, not a single day.
- Combine with volume: a long buildup on heavy volume is stronger than on thin volume.
- Short covering rallies are often sharp but short-lived — they're fuel, not new demand.
- Stocks entering the F&O ban list have OI near the market-wide limit; only position reduction is allowed.
On BullStocks
The F&O dashboard classifies all 200+ F&O stocks every few minutes, using NSE's combined futures and options OI change and the live price move, and ranks the strongest in each bucket.