Who holds the positions — open interest & flow
Until now we've only looked at your position. This episode looks at everyone else's. Open interest, volume, flow and the put/call ratio are the tools that show where the biggest positions sit — and where price tends to get pulled.
- Open interest — who's actually in the trade, and OI clusters as price magnets
- Volume vs open interest — activity versus durable positioning
- Flow and block trades — reading what's happening right now
- The whale trap — why one big trade isn't a thesis
- The put/call ratio — a sentiment gauge that works at extremes
Open interest — who's actually in the trade
Open interest (OI) is the number of open option contracts — how many positions are alive at a given strike and expiry. OI rising means new positions are coming in; OI falling means positions are being closed or have expired. What it doesn't tell you is who's long and who's short — only that positions exist.
And what matters isn't the total OI — it's where it's concentrated: on which strike, on which expiry, calls or puts. A big OI cluster tends to become one of two things: a price magnet (near expiry, price often "pins" close to large OI — so-called pin risk), or a defended zone where price reactions are sharper.
OI also reads differently depending on what price is doing at the same time.
| Price | Open interest | What it suggests |
|---|---|---|
| ↑ up | ↑ rising | New positions support the move — healthy, but watch for overheating at extremes. |
| ↑ up | ↓ falling | Rally from short covering, not conviction — less durable. |
| ↓ down | ↑ rising | Downside positioning is building — hedging, new shorts, protective puts. |
| ↓ down | ↓ falling | Deleveraging and position cleanout — often the end of a downmove. |
Volume vs open interest
These are not the same thing, and confusing them is a classic mistake. Volume is the number of transactions today — activity. Open interest is the number of positions still open. Picture one session at the $65k strike: Trader A buys 5 calls, Trader B sells 5 → volume 5, OI +5. Later both close out → another volume of 5, OI −5. End of day: volume 10, open interest 0. Plenty of activity, zero durable positioning.
So the combination is the signal. High volume with no OI growth is rotation, not new positioning. High volume with rising OI means something is being built — the more meaningful read. High volume with falling OI means somebody is closing big positions, often a player worth watching.
Flow and block trades
Flow is order flow — who's buying and selling what, and when. It's very different from OI: open interest says "positions exist," flow says "right now, somebody is doing something." What you read from it is what's being traded (calls or puts), at what strike and expiry, and whether it looks like speculation, a hedge, or structure (a spread, a butterfly).
| Flow | Possible meanings |
|---|---|
| Call buying | Upside speculation · a short-gamma hedge · chasing momentum |
| Put buying | Hedging · panic protection · a downside bet |
| Call selling | Premium collection · a "won't rally" view · covered calls |
| Put selling | Bullish bias · wanting to buy lower · selling fear |
A block trade is a large, often OTC transaction between institutional players — typically more structural than retail click-flow. Worth checking: is it a new position or a close/roll, and is it consistent with the other signals (price, IV, skew)?
"A whale just bought 5,000 50k-strike puts — there's about to be a dump!" Not necessarily. It could be a hedge on a long spot portfolio, a roll of protection they already held, part of a structure (a risk reversal), or a neutral pre-event volatility bet. The rule: one flow is not a thesis. Look at a series of consistent flows, plus context.
The put/call ratio
A supporting tool, not a primary one. The put/call ratio (P/C) is put volume divided by call volume (or computed on open interest). A high ratio (lots of puts) points to defensive positioning, hedging, fear; a low ratio (lots of calls) points to upside appetite, greed.
One caution: a call can be bought or sold, and a put can be a hedge on a long spot book rather than a short. In isolation — without skew, flow, OI and price — the ratio can mislead, so use it as a complement. It works best at extremes: a P/C above ~1.5 after a panic is often a contrarian signal (fear is already priced in), while a P/C below ~0.5 at a top warns of a possible correction (greed).
Where this leads
You can now see where the market is positioned — the walls, the flow, the mood. But positioning only becomes powerful once you know what the other side has to do about it. Next episode: gamma exposure (GEX) and how dealer hedging quietly turns all these option positions into real movement in spot — the mechanics behind "calls drive rallies" and "puts drive sell-offs."
Free e-book · the whole thing Crypto Options — from your first call to your first edge This episode covers chapters 20–23. Read the complete e-book — free, no signup — for every chapter, diagram and worked example.
