{"schemaVersion":1,"asset":"BTC","reportDate":"2026-09-22","timestamps":{"currentSnapshotAt":"2026-09-22T18:18:00+00:00","previousSnapshotAt":"2026-09-21T18:37:00+00:00","generatedAt":"2026-09-22T18:18:40+00:00"},"comparison":{"status":"available","note":null},"provenance":{"reportArtifact":"published daily report","sourceReport":"BTC","sourceReportHref":"/reports/2026-09-22","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":1790705880114,"availability":"available","unavailableReason":null,"atmIv":{"current":36.5,"previous":39.36,"change":-2.86,"percentChange":-7.27},"rr25":{"current":0.56,"previous":-0.71,"change":1.27,"percentChange":178.87},"bf25":{"current":1.96,"previous":2.43,"change":-0.47,"percentChange":-19.34}},{"tenor":"2W","targetExpiry":1791310680114,"availability":"available","unavailableReason":null,"atmIv":{"current":36.63,"previous":37.47,"change":-0.84,"percentChange":-2.24},"rr25":{"current":0.06,"previous":-0.17,"change":0.23,"percentChange":135.29},"bf25":{"current":1.7,"previous":2.49,"change":-0.79,"percentChange":-31.73}},{"tenor":"1M","targetExpiry":1792693080114,"availability":"available","unavailableReason":null,"atmIv":{"current":36.68,"previous":36.4,"change":0.28,"percentChange":0.77},"rr25":{"current":-0.47,"previous":-0.44,"change":-0.03,"percentChange":-6.82},"bf25":{"current":1.91,"previous":2.34,"change":-0.43,"percentChange":-18.38}},{"tenor":"3M","targetExpiry":1797963480114,"availability":"available","unavailableReason":null,"atmIv":{"current":38.71,"previous":38.78,"change":-0.07,"percentChange":-0.18},"rr25":{"current":-0.78,"previous":-0.38,"change":-0.4,"percentChange":-105.26},"bf25":{"current":2.14,"previous":2.4,"change":-0.26,"percentChange":-10.83}},{"tenor":"6M","targetExpiry":1805825880114,"availability":"available","unavailableReason":null,"atmIv":{"current":39.36,"previous":39.55,"change":-0.19,"percentChange":-0.48},"rr25":{"current":-0.53,"previous":-0.52,"change":-0.01,"percentChange":-1.92},"bf25":{"current":2.37,"previous":2.52,"change":-0.15,"percentChange":-5.95}},{"tenor":"9M","targetExpiry":1813688280114,"availability":"available","unavailableReason":null,"atmIv":{"current":39.89,"previous":40.21,"change":-0.32,"percentChange":-0.8},"rr25":{"current":-0.11,"previous":-0.4,"change":0.29,"percentChange":72.5},"bf25":{"current":2.47,"previous":2.54,"change":-0.07,"percentChange":-2.76}},{"tenor":"1Y","targetExpiry":1821637080114,"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 1420 (98.6111% coverage); returns spanning missing minutes are excluded"}