Put/Call ratio & futures open interest, explained
Last updated: 2026-07-25
The Put/Call ratio (P/C ratio) on Taiwan index options is total put open interest divided by total call open interest across all strikes, published daily by the Taiwan Futures Exchange (TAIFEX). Futures net open interest is total long contracts minus total short contracts held by a group (e.g. foreign investors). Traders watch both as gauges of positioning and sentiment — a rough heuristic, not a timing signal. Descriptive, not investment advice.
What the Put/Call ratio actually measures
For Taiwan index options (TXO), TAIFEX sums the open interest of every put contract across all strike prices, then divides by the same sum for calls. A ratio above 1 means more puts are held open than calls; below 1 means the reverse. Because it uses open interest (positions still outstanding) rather than daily volume, it reflects accumulated positioning, not just one day's trading.
How traders read it — and why that's a convention, not a rule
In Taiwan's options market, where option-selling (writing) is a common retail and institutional strategy, a rising P/C ratio is often read by traders as sellers leaning toward puts — interpreted as relative optimism about downside support. Extreme readings (very high or very low) are sometimes read as a contrarian signal: when positioning gets one-sided, a reversal or short squeeze becomes more discussed. Both readings are market conventions built on Taiwan's specific option-writing structure, not a guaranteed rule — the ratio can stay stretched for a long time before anything happens. Not investment advice.
Futures net open interest: who's net long or short
Net open interest = total long contracts minus total short contracts for a given group. TAIFEX publishes this daily for the three major institutional investors (foreign institutions, investment trusts, dealers) on Taiwan-index futures (TX). A positive net position means that group holds more long than short contracts; a negative one means the reverse. This is the derivatives-side complement to the three investors' cash-market net buy/sell — see how the two relate on the Taiwan institutional investors page.
Where to check these numbers for free
Both are free, official TAIFEX publications: the daily Put/Call ratio page, and the three institutional investors' futures and options trading page (which includes net open interest). Many broker apps and financial data sites repackage the same official numbers, sometimes with added charting.
Positioning data vs order flow and capital pressure
The P/C ratio and futures net open interest are both end-of-day snapshots of accumulated positioning — they tell you where the market stands right now, not how it got there minute by minute. Order flow is the opposite: real-time execution data showing which side is the aggressor. See-Market's daily capital-pressure read sits between the two, derived from price and volume on the equity indices. Read them together for context, not as substitutes. See the flow observatory and the order-flow guides. Not investment advice.
FAQ
What is the Put/Call ratio in one sentence?
Total put open interest divided by total call open interest, across all strikes, on Taiwan index options — published daily by TAIFEX as a gauge of options positioning.
Does a high P/C ratio mean the market will go up?
No. A high ratio is commonly read as sellers leaning toward puts (relative optimism about downside support), and an extreme reading is sometimes discussed as a contrarian signal — but both are market conventions, not guarantees, and the ratio can stay stretched for a long time. Not investment advice.
What is futures net open interest?
Total long contracts minus total short contracts held by a group (e.g. foreign investors) on Taiwan-index futures. Positive means net long, negative means net short. TAIFEX publishes this daily for the three major institutional investors.
Is this the same as the three institutional investors' cash-market data?
No, but they're related. The three investors' cash-market net buy/sell (covered on the Taiwan institutional investors page) is about stocks; futures net open interest and the P/C ratio are the derivatives side — positions in index futures and options. Traders often check both together.
Where can I check the P/C ratio and net open interest for free?
Both are free official TAIFEX publications: the daily Put/Call ratio page, and the three institutional investors' futures and options trading page. Many broker apps repackage the same official numbers.
Not investment advice. The Put/Call ratio and futures net open interest are descriptive, end-of-day positioning data — context, not a buy/sell signal, and the market conventions around reading them are heuristics, not guarantees. Official data: Taiwan Futures Exchange (TAIFEX).