Call open interest in TAIEX options (TXO) rose by 45,879 contracts on Tuesday while put open interest rose by just 6,280, as the benchmark fell 1,612.60 points. The put/call open-interest ratio dropped to 47.77%, its most call-heavy reading of the past three sessions, with Wednesday’s weekly expiry centred on a 46,000 call wall about 6% above the market.
By MoneyTurkey Options Desk
Key points
- Open interest (OI), the number of option contracts still outstanding, in TAIEX options (TXO) rose to 159,184 calls and 76,050 puts at the 3 November close, across all weekly and monthly expiries, according to the Taiwan Futures Exchange (TAIFEX). Call OI rose by 45,879 contracts on the day and put OI by 6,280.
- The put/call OI ratio, which divides put OI by call OI, fell to 47.77% from 61.58% on 2 November and 62.59% on 30 October.
- The three institutional investor groups tracked by TAIFEX together cut their net call position by 11,202 contracts and added 4,951 contracts of net puts. Because every option has a buyer and a seller, that implies other participants, mainly individuals, were the net buyers of calls and net sellers of puts as the market fell.
- The largest call position in the weekly contract expiring on Wednesday 4 November was at the 46,000 strike, about 6.2% above Tuesday’s close of 43,307.54. In the November monthly contract, which expires on 18 November, the largest call position was at 50,000, about 15.5% above.
- Data note: the Taiwan VIX close for 3 November was not verified at the time of writing and is not quoted in this article. Strike-level OI figures come from a third-party digest of TAIFEX data.
The Taiwan Capitalization Weighted Stock Index (TAIEX) fell 1,612.60 points, or 3.59%, to 43,307.54 on Tuesday 3 November, Taiwan News reported, citing the Central News Agency (CNA). It was the seventh-largest one-day points decline on record, Commercial Times (CTEE) said. The index fell below 44,000 a session after losing 45,000.
The options market did not respond with a rush into puts. TXO call OI rose by more than seven times as much as put OI, and the institutional data suggest much of the new call buying came from outside the three big investor groups.
What happened
The TAIEX opened at 44,481.59, down 438.55 points from Monday’s close of 44,920.14, and briefly reached 44,614.64 before selling off through the session. It touched a low of about 43,191.58 and closed less than 120 points above it. Turnover was NT$928.1bn (about US$28.3bn), according to Taiwan News and CNA.
Technology stocks led the decline. Taiwan Semiconductor Manufacturing Co. (TSMC), the index’s largest constituent, fell 1.5% to NT$2,295. MediaTek fell 7.43% to NT$3,675, Delta Electronics 6.27% and ASE Technology 8.61%. Hon Hai Precision Industry (Foxconn) fell 2.19%.
The sell-off came on the same day as Seoul’s. The KOSPI fell 3.59% and the KOSPI 200 about 3.8% as Asian AI and chip stocks followed US technology shares lower, as MoneyTurkey’s KOSPI 200 options piece the same day reported. Taiwan’s Financial Supervisory Commission said the TAIEX’s fall was within the range of major Asian markets, CNA reported.
Kuo Ming-yu (éƒæ˜ŽçŽ‰), manager of the E Sun Taiwan Core Technology Active ETF, told Taiwan News that markets faced uncertainty around the US midterm elections and US monetary policy. She described foreign selling as normal profit-taking and noted that foreign investors still owned about 47% of the Taiwan market. She favoured selective stock picking and said she remained positive on AI optical communications and advanced semiconductor manufacturing over the medium to long term.
Futures fell further than the cash index. The November TAIEX futures contract (TX) settled at 43,353, down 1,874 points, or 4.14%, with OI of 121,861 contracts, up 1,783, according to CTEE. December TX settled at 43,443, down 1,892. That left November futures about 45 points above the cash close, compared with about 307 points on Monday. Foreign institutional investors (FINI) held a net short position of 91,812 TX contracts, 2,433 more than on Monday.
The options book
TXO contracts are European-style, so they can be exercised only at expiry, and cash-settled, with a multiplier of NT$50 per index point, according to TAIFEX. At Tuesday’s close, one contract represented about NT$2.17m of index exposure. Monthly contracts stop trading on the third Wednesday of the delivery month, which for November is 18 November. The first November weekly contract (202611W1) expires on Wednesday 4 November.
TAIFEX’s daily put/call table, which combines all weekly and monthly expiries, showed a sharp shift on Tuesday:
| Date | Put volume | Call volume | P/C volume | Put OI | Call OI | P/C OI |
|---|---|---|---|---|---|---|
| 3 Nov | 217,195 | 271,541 | 79.99% | 76,050 | 159,184 | 47.77% |
| 2 Nov | 148,092 | 157,966 | 93.75% | 69,770 | 113,305 | 61.58% |
| 30 Oct | 419,366 | 461,304 | 90.91% | 46,701 | 74,619 | 62.59% |
Source: TAIFEX, TXO put/call ratio. All expiries combined.
- Open interest: call OI rose 40% in a single session, from 113,305 to 159,184. Put OI rose 9%. Since 30 October, call OI has more than doubled, while put OI has risen by about 63%. Aggregate OI also moves as weekly contracts expire and new ones are listed, so part of the two-session change reflects the expiry calendar.
- Volume: call volume rose 72% from Monday and put volume 47%. The put/call volume ratio fell to 79.99% from 93.75%.
- Weekly walls: in the 202611W1 contract expiring on 4 November, the largest call OI was 5,606 contracts at the 46,000 strike, about 6.2% above Tuesday’s close. The largest put OI was 2,322 contracts at 43,000, about 0.7% below, according to the Acai Protocol daily digest of TAIFEX data. A “call wall” or “put wall” is simply the strike with the most OI. Traders watch these levels because dealer hedging may be concentrated there, but OI alone does not show who is long or short.
- Monthly walls: in the November monthly contract, the largest call OI was 2,501 contracts at 50,000, about 15.5% above the close, and the largest put OI was 1,505 contracts at 40,000, about 7.6% below.
Who was trading
TAIFEX publishes net OI, long positions minus short positions, for three institutional groups. The 3 November figures, compiled by Acai Protocol, were:
| Investor | Calls, net OI | Day change | Puts, net OI | Day change |
|---|---|---|---|---|
| Foreign institutional investors | +3,553 | +1,389 | +3,241 | +1,048 |
| Investment trusts | −19,801 | −4,886 | +627 | +160 |
| Dealers | +4,790 | −7,705 | +1,767 | +3,743 |
| Three groups combined | −11,458 | −11,202 | +5,635 | +4,951 |
Source: TAIFEX via Acai Protocol, 3 November 2026. Combined rows calculated by MoneyTurkey. Net OI is long minus short contracts.
Investment trusts, which already carried a large net short call position, extended it by 4,886 contracts to 19,801. Dealers cut their net long call position by 7,705 contracts to 4,790 and added 3,743 contracts of net puts, turning a net short put position of about 1,976 contracts into a net long of 1,767. Foreign institutions added to both calls and puts.
Taken together, the three groups were net short 11,458 calls and net long 5,635 puts at the close. Since net positions across the whole market sum to zero, the remaining participants, mostly individual traders, held the opposite side. On the day, they added about 11,200 contracts of net long calls and about 4,950 of net short puts.
TAIFEX’s after-hours data for the 3 November trading date showed FINI buying 27,173 calls and selling 27,381, a net 208 calls sold, while buying 25,389 puts and selling 25,019, a net 370 puts bought. Those figures cover only the night session counted towards that date, not the full day, and are small relative to the day-session changes.
Why it matters
A falling put/call ratio during a sharp sell-off is unusual. In most declines, traders buy puts for protection and the ratio rises. On Tuesday, the reverse happened: call OI grew far faster than put OI, and the ratio fell to its lowest level of the three sessions shown.
The institutional data suggest who was behind it. The three groups were net sellers of calls and net buyers of puts on the day, while their counterparties, mostly individual traders, added calls and sold puts. That pattern is consistent with retail traders buying the dip with cheap out-of-the-money calls, while institutions wrote those calls and bought protection. Public data cannot confirm the motive behind any position.
The near-term focus is Wednesday’s weekly expiry. With the index at 43,307.54, the 46,000 call wall is about 2,700 points above the market. The index would need to rise about 6.2% in a single session, more than reversing Tuesday’s fall, for calls at that strike to expire in the money. The 43,000 put wall, by contrast, is less than 1% below the close, so small moves on Wednesday could decide whether those puts expire in the money.
For the November monthly contract, the 50,000 call wall is about 15.5% above the market, with 11 trading days left to the 18 November expiry. The 40,000 put wall is about 7.6% below.
The futures market added to the downside signal. November TX fell 4.14%, more than the cash index, and most of its premium to the cash market disappeared. Foreign institutions extended their net short futures position to 91,812 contracts. Their option positions were small by comparison, which suggests much of their hedging ran through futures rather than options.
What to watch
- 4 November weekly expiry: where the TAIEX settles relative to the 43,000 put wall and the 46,000 call wall in the 202611W1 contract.
- Taiwan VIX: TAIFEX’s TAIEX Options Volatility Index, calculated using the CBOE VIX methodology, will show how far option prices are pricing in further large moves. The 3 November reading was not verified at the time of writing.
- Put/call ratio: whether the OI ratio stays below 50% or rebounds as traders buy protection, and whether retail call buying continues if the index keeps falling.
- Investment trusts and dealers: whether trusts keep adding to their net short call position and whether dealers continue to buy puts.
- Foreign futures short: whether FINI extend their net short TX position beyond 91,812 contracts, and whether the futures premium to the cash index turns into a discount.
- 18 November monthly expiry: how much call OI builds at or near the 50,000 strike, and whether the 40,000 put wall attracts new positions.
- US overnight: the US midterm elections and US chip stocks will set the tone for Taipei and Seoul on Wednesday.
Sources
- Taiwan News (English), Charlotte Lee: TAIEX sheds 1,612 points to fall below 44,000 (3 November 2026)
- CNA (Chinese): TAIEX falls 1,612.60 points (3 November 2026)
- CNA (Chinese): TAIEX falls 1,612 points; FSC says decline within range of major Asian markets (3 November 2026)
- Commercial Times / CTEE (Chinese): TAIEX falls 1,612 points, seventh-largest points drop on record; 74 stocks limit-down (3 November 2026)
- Taiwan Futures Exchange (Chinese): TXO put/call ratio
- Taiwan Futures Exchange (English): TAIEX Options (TXO) contract specifications
- Acai Protocol (Chinese): TAIEX futures and options daily positioning digest, 3 November 2026, compiled from TAIFEX data
- MoneyTurkey: SK Hynix’s Seoul options book held 28 calls for every put before 5% slide (3 November 2026)
- MoneyTurkey: KOSPI 200 options still leaned towards calls, with VKOSPI above 53, before index fell 3.8% (3 November 2026)
This article is for information purposes only and does not constitute investment advice. MoneyTurkey does not recommend buying or selling any security, option or other financial instrument. Options carry a high risk of rapid loss.
