BTCSpot-index 24h -0.37%1W ATM IV 34.76%1W RR25 -0.37 vol pts1W BF25 Unavailable1W IV − 7D RV Unavailable
One-week relative put-side volatility increased, with no qualifying market-moving news retained. No additional qualifying evidence was identified for that session.
Previous report, watch levels and methodology
One-week surface context; the published headline retains its original evidence basis. Cutoffs 11 Sept, 16:29 UTC to 12 Sept, 16:29 UTC.
Previous publication · research context
2026-09-11: “Bitcoin options see one-week implied volatility fall”
Previous publication cutoff 11 Sept, 16:29 UTC. Today’s market comparison starts at 11 Sept, 16:29 UTC. Snapshot clocks align for the measured comparison below.
BTC 1W ATM IV: prior change -2.65 → current change -1.58 volatility points; same direction.
BTC 1W RR25: prior change -0.68 → current change -0.48 volatility points; same direction.
A structured watchlist was not recorded or could not be verified in the prior edition; this compares measured changes only.
Next daily cutoff: measurable checks
These checks are reconstructed from this edition’s stored endpoints; they were not recorded in the original report.
Hold the observed level: BTC 1W ATM IV ≤ 34.76 percent at . Current level 34.76; threshold is the current observed endpoint.
Full retrace: BTC 1W ATM IV ≥ 36.34 percent at . Current level 34.76; threshold is the previous observed endpoint.
Measurement basis and receipt
These are observed-level conditions for the next aligned cutoff, with no forecast or trade action. Spot uses exact index endpoints where available; ATM IV is quoted in percent and its change, RR25 and BF25 in volatility points. Derived from verified legacy artifact endpoints.
BTC:atmIv:1W:observed-current-level: rows[asset=BTC].report.tenors[tenor=1W].atmIv.previous; rows[asset=BTC].report.tenors[tenor=1W].atmIv.current; rows[asset=BTC].report.tenors[tenor=1W].atmIv.change; evaluation window 2026-09-12T16:29:00+00:00 to 2026-09-13T16:29:00+00:00.
BTC:atmIv:1W:observed-previous-level: rows[asset=BTC].report.tenors[tenor=1W].atmIv.previous; rows[asset=BTC].report.tenors[tenor=1W].atmIv.current; rows[asset=BTC].report.tenors[tenor=1W].atmIv.change; evaluation window 2026-09-12T16:29:00+00:00 to 2026-09-13T16:29:00+00:00.
Chart notes
Combined surface read: ATM IV fell (BTC); RR25 moved toward puts (BTC).
02 · Options market read
What the volatility surface did.
No headline tenor had comparable observations at both endpoints; unavailable values remain suppressed in the tables and charts.
Derived directly from structured Derivasys surface data
03 · Catalyst check
11 Sept 2026, 16:29 UTC to 12 Sept 2026, 16:29 UTC
No catalyst assigned.
No qualifying context was found in the monitored news sources for this reporting window.
04 · Detailed analysis
What changed across the BTC volatility surface.
Implied versus realised
At the 16:29 UTC cutoff, 1W ATM IV was 34.76%, 3.34 volatility points above seven-day realised volatility of 31.42%; 24-hour realised volatility was 20.73% and 30-day realised volatility was 39.42%.
Front end
Front-end ATM IV is unavailable because comparable observations were not present at both snapshots.
Long end
Long-dated ATM IV is unavailable because comparable observations were not present at both snapshots.
Skew
RR25 is unavailable because comparable observations were not present at both snapshots.
Largest standard-tenor move
The largest standard-tenor ATM IV move was -1.58 volatility points at 1W, to 34.76%.
Universe roll: added 16SEP26; removed 12SEP26. Comparisons use common expiries only.
RR25 is unavailable because comparable observations were not present at both snapshots. Negative RR25 denotes a richer 25-delta put wing under the call-minus-put convention.
Contracts with fewer than 2 full days to expiry remain in the tables but are excluded from headline rankings. Settlement proximity, time decay, changing liquidity and fewer quotes can exaggerate their changes.
0.6d
ATM IV change
13SEP26, -9.58 vol pts1.6d
ATM IV change
14SEP26, -4.31 vol pts
10 · Volatility term structure
Today against the previous 24-hour snapshot.
Only fixed tenors bracketed by listed expiries at both snapshots are charted. The listed-expiry table preserves the observable exchange maturities underneath those interpolated points.
CurrentComparison snapshot
Suppressed outside the observable listed-expiry range: 1Y.
Expiry
Time left
Forward now (USD)
Forward change (USD)
ATM IV now
ATM IV change
RR25 change
BF25 change
13SEP26Expiry effect
0.6 days
77,355.45
-375.10 USD
15.13%
-9.58 vol pts
-0.01 vol pts
Unavailable
14SEP26Expiry effect
1.6 days
77,360.02
-378.65 USD
21.14%
-4.31 vol pts
-0.39 vol pts
Unavailable
15SEP26
2.6 days
77,378.15
-372.23 USD
25.74%
-3.49 vol pts
-0.60 vol pts
Unavailable
18SEP26
5.6 days
77,411.55
-373.53 USD
35.00%
-1.43 vol pts
-0.54 vol pts
Unavailable
25SEP26
12.6 days
77,451.02
-370.34 USD
34.31%
-1.23 vol pts
+0.20 vol pts
Unavailable
2OCT26
19.6 days
77,518.34
-375.18 USD
34.86%
-0.70 vol pts
+0.02 vol pts
Unavailable
30OCT26
47.6 days
77,794.11
-391.04 USD
35.78%
-0.74 vol pts
+0.25 vol pts
Unavailable
27NOV26
75.6 days
78,094.45
-389.43 USD
37.67%
-0.66 vol pts
+0.40 vol pts
Unavailable
25DEC26
103.6 days
78,418.87
-384.50 USD
38.13%
-0.75 vol pts
+0.53 vol pts
Unavailable
26MAR27
194.6 days
79,355.65
-378.41 USD
39.28%
-0.46 vol pts
+0.13 vol pts
Unavailable
25JUN27
285.6 days
80,372.41
-375.52 USD
40.51%
-0.25 vol pts
+0.23 vol pts
Unavailable
11 · Smile movement
Reconstructed SVI smiles for every common expiry.
Each overlay uses the stored five-parameter SVI fit and the snapshot-specific time to expiry. Ultra-short expiries are displayed but do not determine the headline ranking.
13SEP26rotation towards calls · wing steepening14SEP26rotation towards puts · wing steepening15SEP26rotation towards puts · wing steepening18SEP26rotation towards puts · wing steepening25SEP26wing steepening2OCT26wing steepening30OCT26parallel shift lower27NOV26parallel shift lower25DEC26rotation towards calls26MAR27parallel shift lower25JUN27parallel shift lower
Surface movement heatmap
Each cell is the fitted IV change in volatility points. Rows are listed expiries; columns run from the put wing through ATM to the call wing.
IV lowerIV higher
13SEP26
14SEP26
15SEP26
18SEP26
25SEP26
2OCT26
30OCT26
27NOV26
25DEC26
26MAR27
25JUN27
-0.30kATM+0.30k
Completed-session cross-asset context
Crypto volatility against US equity risk.
BTC 30-day implied volatility was 2.2 times VIX, while its 30-session return correlation with SPX was low at 0.17.
Implied-volatility premium
BTC 30-day ATM IV was 35.17%, against VIX at 15.84: a 19.33-point spread and 2.22× ratio.
Daily-close realised-volatility regime
BTC reported crypto realised volatility was 33.31%, versus SPX reported realised volatility of 8.99%. The spread ranked at percentile rank 36.6% of 232 prior observations.
Equity co-movement
Return correlation with SPX was 0.167 over 30 aligned sessions and 0.296 over 60 sessions. VIX9D, VIX and VIX3M closed at 14.47, 15.84 and 18.60.
RV comparison basis unverified: this edition does not record the recognised provider methodology for both horizons and annualisation conventions. The displayed spread rank does not establish matched-horizon comparability.
As of 11 Sept 2026, 20:00 UTC. Implied volatility and completed-session realised volatility use their respective observation windows shown above.
Evidence and methodology
DerivaSys persisted market-context-v1. Crypto RV is annualised using sqrt(365); SPX RV uses sqrt(252).
RV observation windows and sampling
The RV comparisons use one-minute index returns, annualised on a 365-day basis. No coverage policy was recorded in this edition; read the recorded window availability and coverage below.
Evidence, source data and methodology
Report comparison baseline → current snapshot
2026-09-11 16:29:00 UTC → 2026-09-12 16:29:00 UTC
Changes use these stored market-snapshot baselines. The comparison baseline may differ from the snapshot used in the previous published edition.
Reader summary (BF-specific claims withheld)
Bitcoin one-week RR25 fell 0.48 volatility points to -0.37 volatility points, shifting relative volatility toward puts and leaving puts richer than calls at the cutoff. Bitcoin’s 24-hour spot-index return was -0.37%, while one-week ATM IV of 34.76% remained 3.34 points above seven-day realised volatility, according to DerivaSys data.
At report cutoff · Levels and stored endpoint changes
What matters now
Vol: BTC 1W ATM IV 34.76% · Δ -1.58 vol pts
Skew: BTC 1W RR25 -0.37 vol pts · Δ -0.48 vol pts
Curve: BTC 6M minus 1W ATM IV spread +4.43 vol pts · spread Δ +1.10 vol pts
Vol
BTC 1W ATM IV 34.76% · Δ -1.58 vol ptspercentile rank 48.2% by absolute move · full history (n=141)
Technical appendix: measurement and history provenance
Original edition evidence follows unchanged. Its BF slots retain the original full fly25 or unverified basis; these receipts do not validate canonical BF25 history or ranks.
These diagnostics preserve the fitted-surface audit trail without competing with the main market story.
Show SVI parameter changes and normalized Greeks
SVI diagnostics
Daily movement in a, b, rho, m and sigma.
Among ranking-eligible expiries, the largest absolute rho change occurred at 18SEP26; the largest sigma change occurred at 2OCT26.
Expiry
Δ a
Δ b
Δ rho
Δ m
Δ sigma
Smile classification
13SEP26
+0.02800
-0.05300
+0.00270
-0.00130
-0.13900
rotation towards calls, wing steepening
14SEP26
+0.02480
-0.02630
-0.04140
-0.02070
-0.17610
rotation towards puts, wing steepening
15SEP26
+0.03080
-0.03160
-0.02730
-0.01430
-0.15270
rotation towards puts, wing steepening
18SEP26
+0.01340
-0.01110
-0.15830
-0.08680
-0.05040
rotation towards puts, wing steepening
25SEP26
+0.00490
-0.00550
-0.10820
-0.06370
-0.01570
wing steepening
2OCT26
+0.04130
-0.02580
-0.00500
+0.03440
-0.15290
wing steepening
30OCT26
+0.02470
-0.01660
-0.04730
-0.01190
-0.08540
parallel shift lower
27NOV26
-0.00390
+0.00810
-0.04840
-0.05710
+0.00340
parallel shift lower
25DEC26
-0.00080
+0.00310
-0.00970
-0.02250
-0.01140
rotation towards calls
26MAR27
+0.04130
-0.01620
-0.00280
+0.01610
-0.09940
parallel shift lower
25JUN27
+0.01430
-0.00640
+0.03070
+0.02960
-0.03620
parallel shift lower
Current surface characteristics
Where normalized model Greek intensity is highest.
These are comparable Black-forward Greeks for a one-BTC ATM-forward call at each listed expiry—not portfolio exposure, open interest or a prediction of dealer positioning.
Thresholds are asset-specific policies recorded in this edition. Each window is assessed independently; returns spanning gaps are excluded. Partial estimates may miss volatility during gaps.
RV coverage and methodology
BTC · Unavailable · Surface cutoff 12 Sept 2026, 16:29:00 UTC · 7D coverage not recorded / not recorded required · largest 7D gap not recorded / not recorded maximum · maximum gap not recorded. RV suppressed — valid 7D coverage was not recorded. Full 7D coverage policy was not recorded.
Fixed-tenor measures are published only when listed expiries bracket the target at both comparison snapshots. Targets outside either observable range are suppressed, not extrapolated; headline rankings use only supported tenors.
Smile reconstruction
Listed-expiry smiles are reconstructed from stored SVI total-variance parameters on a fixed log-moneyness grid.
Ultra-short expiries
Expiries with fewer than 2 full days remaining stay in detailed tables but are excluded from headline rankings. Settlement proximity, time decay, changing liquidity and fewer quotes can exaggerate their changes.
Greek normalization
Black forward Greeks for a normalized one-BTC ATM-forward call, zero rate, fitted SVI IV
Catalyst policy
Only sufficiently relevant, reliably sourced events are shown; otherwise no catalyst is assigned.
