OI Walls are strikes with statistically significant open interest concentration — outliers that often act as reference points for price.
QuantRadar aggregates open interest across all expiries for each strike, then runs a rolling z-score within a local ±10-strike window. Strikes flagged as OI Walls have z-scores above 2.0 — meaning their OI is more than 2 standard deviations above the local average. These represent unusually large institutional positions.
OI Walls are reference points, not guarantees. Large OI at a strike creates two opposing forces: dealers hedging around that strike create a gravitational pull toward it (pinning), but a break through an OI Wall can trigger rapid hedging activity that accelerates the move. Know which regime you're in (positive vs negative GEX) before deciding whether to expect a pin or a break.
GEX tells you about dealer gamma positioning (the direction of hedging pressure). OI Walls tell you where large open interest sits (potential pinning points). They often coincide — when a GEX level also has an OI Wall, the level has double confirmation.