Module 1 · Options Levels Basics
OI Walls as Support/Resistance
Call walls, put walls, and the magnet/barrier idea.
In this lesson you'll
- Read high-OI strikes as potential S/R
- Define call wall and put wall (net gamma)
- Hold the idea loosely (it depends on the regime)
A strike holding very large OI can behave as intraday support or resistance. The proposed mechanism, under the usual convention (the public sells calls and buys puts, so dealers end up long calls and short puts): at the call wall dealers are long gamma, so their hedge sells into the rally and acts as a brake; at the put wall they are short gamma, so their hedge sells into the decline, and when that floor holds it comes from other things, such as holders taking profit on the puts. Treat it as a tendency, not a rule.
- Call Wall — the strike with the highest concentration of net call gamma; treated as resistance / the top of the expected range.
- Put Wall — the strike with the highest concentration of net put gamma; treated as support / the bottom of the range.
Key takeaways
- Large-OI strikes can act as intraday support/resistance; at the call wall dealer hedging helps brake the rally, at the put wall the floor has other causes — a tendency, not a rule.
- Call wall = top of expected range (resistance); put wall = bottom (support).
- They're defined on NET GAMMA concentration, not raw OI alone.
- Same strike can pin or fail-and-accelerate depending on the gamma regime.
Check your understanding
Pick an answer to reveal instant feedback. Answer every question to complete the lesson.
Why that's off: That's the put wall (support).
Why that's off: It's a range reference, not the close.
Why that's off: It's a modeled level, not a guarantee.
The call wall (highest net call gamma strike) is treated as resistance / the top of the expected range — under the usual convention dealers are long those calls, so their hedge tends to sell the underlying as price rises toward the strike, acting as a brake. Above the strike that damping thins out and the move can extend.
Why that's off: Raw OI is the rough heuristic; net gamma is the refinement.
Why that's off: Volume isn't the basis for the wall definition.
Why that's off: The VIX is overall index vol, not a per-strike wall.
Modern definitions (e.g., SpotGamma) use net gamma concentration, a refinement over the simpler 'biggest OI strike' idea, because it's gamma that drives the hedging flows.
Educational content only. Nothing here is financial or trading advice. Order-flow and options patterns shift probabilities; they never guarantee outcomes.