Delta-based 25-delta skew + ATM IV for one expiry
25-delta skew computed IN DELTA SPACE from the snapshot's contract deltas: implied volatility is linearly interpolated at call delta +0.25 and put delta -0.25 between the adjacent bracketing contracts, and skew_25d = iv_put_25d - iv_call_25d (positive = downside protection priced over upside). The raw call_iv_skew/put_iv_skew strike rows of /iv-surface are the strike-space INPUT view; this endpoint answers in the delta convention practitioners quote. Contracts failing the shared IV plausibility gate (API-1.8) or missing a delta are excluded and counted - the literal-0.0 IV marker never enters the formula. A target outside the reliable chain's delta range yields null, never an extrapolated number. Defaults to the nearest expiry; error codes match /snapshot.
Path parameters
Underlier ticker.
Underlier ticker.
Query parameters
Optional expiry (YYYY-MM-DD). Defaults to the nearest by days_to_expiration.
Optional expiry (YYYY-MM-DD). Defaults to the nearest by days_to_expiration.
Optional snapshot date (YYYY-MM-DD). Defaults to the latest cycle.
Optional snapshot date (YYYY-MM-DD). Defaults to the latest cycle.
Response
25d skew + ATM IV payload.
Example response
{
"data": {
"symbol": "SPY",
"call_25d_source": "interpolated"
},
"meta": {
"endpoint": "/api/v1/fred/us/cpi",
"data_time": "2026-04-16T14:30:00Z",
"response_time": "2026-04-16T14:30:12Z",
"provider": "Sugra API v1.0.1",
"source": "sugra_crypto",
"attribution": "Short interest and Reg SHO daily short volume data is owned by and sourced from FINRA (Financial Industry Regulatory Authority).",
"fallback_chain": [
"sugra_crypto",
"sugra_finance"
]
}
}