{"schemaVersion":1,"asset":"BTC","reportDate":"2026-09-23","timestamps":{"currentSnapshotAt":"2026-09-23T19:20:00+00:00","previousSnapshotAt":"2026-09-22T19:20:00+00:00","generatedAt":"2026-09-23T19:20:49+00:00"},"comparison":{"status":"available","note":null},"provenance":{"reportArtifact":"published daily report","sourceReport":"BTC","sourceReportHref":"/reports/2026-09-23","source":"Derivasys proprietary historical SVI surface database","comparison":"Nearest successful surface snapshots approximately 24 hours apart","rrConvention":"25-delta call IV minus 25-delta put IV","bfConvention":"Average 25-delta wing IV minus ATM forward IV","fixedTenors":"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.","realisedVolatility":null},"tenors":[{"tenor":"1W","targetExpiry":1790796000076,"availability":"available","unavailableReason":null,"atmIv":{"current":34.13,"previous":36.59,"change":-2.46,"percentChange":-6.72},"rr25":{"current":-1.89,"previous":1.16,"change":-3.05,"percentChange":-262.93},"bf25":{"current":2.15,"previous":2.04,"change":0.11,"percentChange":5.39}},{"tenor":"2W","targetExpiry":1791400800076,"availability":"available","unavailableReason":null,"atmIv":{"current":34.57,"previous":36.52,"change":-1.95,"percentChange":-5.34},"rr25":{"current":-1.41,"previous":0.54,"change":-1.95,"percentChange":-361.11},"bf25":{"current":1.95,"previous":1.82,"change":0.13,"percentChange":7.14}},{"tenor":"1M","targetExpiry":1792783200076,"availability":"available","unavailableReason":null,"atmIv":{"current":34.94,"previous":36.45,"change":-1.51,"percentChange":-4.14},"rr25":{"current":-1.33,"previous":-0.31,"change":-1.02,"percentChange":-329.03},"bf25":{"current":1.99,"previous":1.91,"change":0.08,"percentChange":4.19}},{"tenor":"3M","targetExpiry":1798053600076,"availability":"available","unavailableReason":null,"atmIv":{"current":37.61,"previous":38.61,"change":-1,"percentChange":-2.59},"rr25":{"current":-1.22,"previous":-0.74,"change":-0.48,"percentChange":-64.86},"bf25":{"current":2.12,"previous":2.14,"change":-0.02,"percentChange":-0.93}},{"tenor":"6M","targetExpiry":1805916000076,"availability":"available","unavailableReason":null,"atmIv":{"current":38.84,"previous":39.33,"change":-0.49,"percentChange":-1.25},"rr25":{"current":-0.56,"previous":-0.34,"change":-0.22,"percentChange":-64.71},"bf25":{"current":2.34,"previous":2.36,"change":-0.02,"percentChange":-0.85}},{"tenor":"9M","targetExpiry":1813778400076,"availability":"available","unavailableReason":null,"atmIv":{"current":39.54,"previous":39.89,"change":-0.35,"percentChange":-0.88},"rr25":{"current":-0.38,"previous":-0.03,"change":-0.35,"percentChange":-1166.67},"bf25":{"current":2.38,"previous":2.47,"change":-0.09,"percentChange":-3.64}},{"tenor":"1Y","targetExpiry":1821727200076,"availability":"unavailable","unavailableReason":"The target tenor falls outside the listed-expiry range at one or both snapshots; extrapolated values are suppressed.","atmIv":{"current":null,"previous":null,"change":null,"percentChange":null},"rr25":{"current":null,"previous":null,"change":null,"percentChange":null},"bf25":{"current":null,"previous":null,"change":null,"percentChange":null}}],"realisedVolatility":null,"realisedVolatilityUnavailableReason":"Canonical BTC index coverage for 24h is incomplete: expected 1440 one-minute returns, found 1415 (98.2639% coverage); returns spanning missing minutes are excluded"}