US · Put-Call Ratio

The whole chain, not a window — and that is the difference from the India board. That one scrapes Sensibull because NSE's own site is blocked, and a scrape returns only what the page renders: roughly ±6.7% around ATM for NIFTY. Its band reading is a limitation dressed as a choice. CBOE publishes every contract as plain JSON on a public CDN — 29,282 SPX contracts in one request, open interest and volume on each — so here the whole-chain ratio is the headline and the band is secondary, which is the right way round.

The two scopes usually disagree, and the gap is the point. The whole chain includes far out-of-the-money puts bought as crash insurance, which inflate it; the ATM band is near-the-money positioning. A whole-chain reading far above the band one says the hedging is happening well below the market, not that anyone expects to trade there.

Open interest and volume answer different questions. Open interest is positioning that has accumulated and only settles overnight, so it barely moves intraday. Volume is what traded today — more responsive, and noisy in the first half-hour. Both are published rather than one being picked for you.

What this is not. A put-call ratio is a positioning statistic, not a signal, and index puts in particular are bought as hedges against portfolios the ratio cannot see — so a high reading is at least as likely to mean “hedged” as “bearish”. Nothing here is backtested, and the strategy work in this stack has repeatedly found that readings like this one do not survive as entry filters.

SPX, NDX and RUT now list daily expiries, so the nearest expiry is often zero days out. A 0DTE row carries open interest that largely settled at yesterday's close while its volume is entirely today's — the two halves of that row are not the same age, and the days-to-expiry is shown on every row so it is never ambiguous.