SPX · CALLS · OCT 21Settled

Open interest in SPX calls expiring Oct 21 rose 80,070 at the Oct 20 settlement

As of Oct 20, 2026 settlement. Source: Cboe settlement open interest archive.

On the page at squawkflow.com/options-flow/2026-10-20/spx-calls-oct-21-2026-open-interest-change: the evidence table and the rule this settlement figure passed; and up to six other SPX snapshots from Oct 20, 2026.

78,048 to 158,118 contracts between the Oct 19 and Oct 20 settlements, 103% of the prior figure.

Evidence

The numbers behind this snapshot, Oct 20, 2026 settlement. Open interest change, not trades; it does not say which side opened or closed.
Measure	Value
Open interest, earlier settlement	78,048
Open interest, later settlement	158,118
Change (contracts)	+80,070
Change as a share of the earlier figure	103%
Earlier settlement	Oct 19, 2026
Later settlement	Oct 20, 2026
Days to expiry	1

Rule: |change| >= 10000 or (>= 2000 and >= 50% of prior), and |change share| >= 2.0 x bucket median; prior OI >= 1000
Values that cleared it: Change: 80,070; Change as a share of the earlier figure: 1.0259
Contracts traded behind each figure: Open interest changed: 122
Baseline: median absolute open interest change share, contracts within a week: 0.196
Baseline window: last 20 sessions
Baseline n: 20
Claim level: 0, a reported fact

This snapshot is itself a settlement figure, so it has no follow-up of its own.

SPXPDEC 4Open interest change
Settled
Open interest in SPX puts expiring Dec 4 rose 120,086 at the Oct 20 settlement
18,814 to 138,900 contracts between the Oct 19 and Oct 20 settlements, 638% of the prior figure.
Source: Cboe settlement open interest archiveDetails