Guides
Every page on this site shows measurements rather than opinions. These guides explain what those measurements mean, how they are calculated, and — as importantly — where they mislead.
All guides
What is change in OI in an option chain?
The plain definition, how to read it on calls and puts, how it differs from volume, and the mistakes beginners make.
Option writer positioning: gamma, rotation and the pin
Why open interest overstates far strikes, why there is no gamma flip in this market, how to spot writers rotating sides before a turn, and how the straddle prices the expected move.
How to read the OI change chart
Where option writers are committing capital, why put writing below spot builds support, and four ways traders misread open interest.
Which strike gains most from the next move
Why the obvious strike is usually the wrong one, how the estimates are priced, and why the headline gain is optimistic.
How support and resistance levels are found
The clustering method behind the lines, why premium levels differ from index levels, and how much weight they deserve.
Stocks that hold up when the index falls
Why falling less than the index is not strength, and how measuring against a stock's own history fixes it.
Where to start
New to open interest? Start with what change in OI means. If you already know, the OI change guide goes further — it underpins most of what the other pages show. If you trade stocks intraday, start with relative strength. For the layer above positioning — the hedging flow it generates, and which side writers are rotating onto — see option writer positioning.
For the precise formulas behind every number, the method page is the reference.