Live options risk-pricing context · By CoinNudge Research · Method reviewed 2026-09-11 · Guide updated 2026-09-12 · Live sources · Data observed at · Calculation deribit-25delta-skew-1.1 · Auto-refresh about every 900 seconds
Bitcoin and Ethereum options skew today
Current answer: As of , using Deribit BTC and ETH option instruments and public book summaries: ETH's 18.7-day expiry has the largest displayed 25-delta skew at 1.92 volatility points: put IV 53.65% minus call IV 51.73%. Positive skew means downside protection is richer, not that price must fall.
Live sources
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Current source-backed snapshot
This page compares the implied volatility of approximately 25-delta puts and calls for open Deribit Bitcoin and Ethereum expiries from two to 45 days. Positive skew means the selected downside put carries higher mark IV than the comparable upside call; negative skew means the call carries higher IV. The page also shows ATM IV, wing curvature and put/call OI context. Skew describes relative option pricing—not the probability or direction of the next price move.
Input documentation: Deribit public instruments · Deribit book summaries · CoinNudge methodology
Observation window: Open expiries from 2 to 45 days; model-derived 25-delta put IV minus call IV
Calculation cadence: Auto-refresh about every 900 seconds
Calculation version: deribit-25delta-skew-1.1
Download current dataset: JSON · CSV Raw values retain the dataset's published precision. Free fair-use limit: 60 requests per minute per IP, shared across all Research JSON and CSV endpoints.
| Asset / expiry | 25Δ put instrument | 25Δ call instrument | Put minus call skew | Selected deltas | Interest rates | ATM instrument / wing |
|---|---|---|---|---|---|---|
| BTC · 2026-09-16 08:00:00 UTC · 2.7 days · T=0.00735y | BTC-16SEP26-75500-P · 35.07% IV · $75,500.00 | BTC-16SEP26-79000-C · 35.77% IV · $79,000.00 | -0.70 vol points · calls richer | -0.235 / 0.222 | 0.000000% / 0.000000% | BTC-16SEP26-77000-P · 34.53% IV · 0.89 wing points |
| BTC · 2026-09-17 08:00:00 UTC · 3.7 days · T=0.01009y | BTC-17SEP26-75000-P · 40.30% IV · $75,000.00 | BTC-17SEP26-79500-C · 40.51% IV · $79,500.00 | -0.21 vol points · calls richer | -0.238 / 0.235 | 0.000000% / 0.000000% | BTC-17SEP26-77000-C · 38.99% IV · 1.41 wing points |
| BTC · 2026-09-18 08:00:00 UTC · 4.7 days · T=0.01283y | BTC-18SEP26-75000-P · 40.60% IV · $75,000.00 | BTC-18SEP26-80000-C · 41.54% IV · $80,000.00 | -0.94 vol points · calls richer | -0.262 / 0.227 | 0.000000% / 0.000000% | BTC-18SEP26-77000-P · 39.56% IV · 1.51 wing points |
| BTC · 2026-09-25 08:00:00 UTC · 11.7 days · T=0.03201y | BTC-25SEP26-74000-P · 38.05% IV · $74,000.00 | BTC-25SEP26-81000-C · 37.61% IV · $81,000.00 | 0.44 vol points · puts richer | -0.256 / 0.248 | 0.000000% / 0.000000% | BTC-25SEP26-77000-C · 36.72% IV · 1.11 wing points |
| BTC · 2026-10-02 08:00:00 UTC · 18.7 days · T=0.05119y | BTC-2OCT26-73000-P · 38.12% IV · $73,000.00 | BTC-2OCT26-82000-C · 36.95% IV · $82,000.00 | 1.17 vol points · puts richer | -0.242 / 0.251 | 0.000000% / 0.000000% | BTC-2OCT26-77000-P · 36.50% IV · 1.03 wing points |
| ETH · 2026-09-16 08:00:00 UTC · 2.7 days · T=0.00735y | ETH-16SEP26-2420-P · 48.41% IV · $2,420.00 | ETH-16SEP26-2560-C · 48.94% IV · $2,560.00 | -0.53 vol points · calls richer | -0.238 / 0.263 | 0.000000% / 0.000000% | ETH-16SEP26-2500-P · 46.79% IV · 1.88 wing points |
| ETH · 2026-09-17 08:00:00 UTC · 3.7 days · T=0.01009y | ETH-17SEP26-2400-P · 54.62% IV · $2,400.00 | ETH-17SEP26-2580-C · 54.04% IV · $2,580.00 | 0.58 vol points · puts richer | -0.240 / 0.268 | 0.000000% / 0.000000% | ETH-17SEP26-2500-P · 52.09% IV · 2.24 wing points |
| ETH · 2026-09-18 08:00:00 UTC · 4.7 days · T=0.01283y | ETH-18SEP26-2400-P · 54.26% IV · $2,400.00 | ETH-18SEP26-2600-C · 54.70% IV · $2,600.00 | -0.44 vol points · calls richer | -0.262 / 0.255 | 0.000000% / 0.000000% | ETH-18SEP26-2500-P · 52.06% IV · 2.42 wing points |
| ETH · 2026-09-25 08:00:00 UTC · 11.7 days · T=0.03201y | ETH-25SEP26-2350-P · 54.33% IV · $2,350.00 | ETH-25SEP26-2650-C · 52.71% IV · $2,650.00 | 1.62 vol points · puts richer | -0.255 / 0.275 | 0.000000% / 0.000000% | ETH-25SEP26-2500-P · 51.65% IV · 1.87 wing points |
| ETH · 2026-10-02 08:00:00 UTC · 18.7 days · T=0.05119y | ETH-2OCT26-2300-P · 53.65% IV · $2,300.00 | ETH-2OCT26-2700-C · 51.73% IV · $2,700.00 | 1.92 vol points · puts richer | -0.232 / 0.269 | 0.000000% / 0.000000% | ETH-2OCT26-2500-C · 50.97% IV · 1.72 wing points |
Current source health
- deribit options: live; last success 2026-09-13 15:35:13 UTC
The 25-delta contracts are selected with a Black–Scholes delta calculated from Deribit mark IV, underlying, strike, rate and time. This is a live Deribit surface observation, not a historical percentile, option valuation or directional forecast.
How to read this page
- Positive skew means downside puts are priced with higher IV than comparable upside calls.
- Negative skew means upside calls carry higher IV; it does not guarantee an upside move.
- Compare expiries because short- and longer-dated protection can price differently.
- Check selected deltas and contract count before trusting a sparse surface.
What can this page tell you quickly?
- Best for
- Seeing whether BTC or ETH option wings currently price more downside or upside volatility.
- Venue
- Deribit public BTC and ETH options.
- Expiry range
- Two to 45 days with an acceptable pair near 25 delta.
- Do not infer
- Skew is not a probability, price target or recommendation to buy an option.
What does positive or negative 25-delta skew mean?
Positive put-minus-call skew means the selected out-of-the-money put has higher implied volatility than the comparable call. It can reflect demand for downside protection, supply imbalance or surface mechanics. Negative skew can reflect stronger upside-call pricing, but neither sign reveals who initiated the trade or what realized volatility will be.
The useful observation is relative pricing across comparable deltas and expiries. Reading one strike or raw option price would mix moneyness, underlying level and time value.
| Skew state | Observed option pricing | Possible context | Not established |
|---|---|---|---|
| Positive | 25d put IV above 25d call IV | Downside protection priced richer | Price will fall |
| Near zero | Wing IVs similar | More balanced relative pricing | Low volatility |
| Negative | 25d call IV above 25d put IV | Upside calls priced richer | Price will rise |
| Different by expiry | Term structure disagrees | Event or horizon-specific pricing | One expiry is correct |
How does CoinNudge select a 25-delta option?
Deribit's bulk book summary provides mark IV, underlying price and contract identity but not a bulk delta field. CoinNudge calculates a standard Black–Scholes delta for each open contract, then selects the nearest call and put to the target deltas.
The selected delta, strike and contract count remain in the downloadable dataset. If a surface lacks a sufficiently close wing, that expiry is omitted rather than substituting a distant strike.
| Input | Source | Use | Quality control |
|---|---|---|---|
| Underlying | Deribit summary | Spot/future reference in delta | Must be positive |
| Mark IV | Deribit summary | Volatility input | Must be positive |
| Strike and expiry | Deribit instrument | Moneyness and time | Open contracts only |
| Delta distance | CoinNudge calculation | 25d pair selection | Maximum 0.12 from target |
Why compare skew across several expiries?
Short-dated skew reacts quickly to immediate hedging or event risk but can be noisy and sensitive to a small contract set. Longer-dated skew reflects a wider risk horizon and may remain stable while the front expiry changes sharply.
A front-end positive spike with stable longer expiries identifies localized protection demand. Broad positive skew across maturities is a different surface shape, but still does not prove a future decline.
| Pattern | What to investigate | Supporting field | Caution |
|---|---|---|---|
| Front skew jumps | Near-term event or hedging demand | Days to expiry | Short surface can be sparse |
| All expiries positive | Persistent downside-rich pricing | Contract counts and ATM IV | No direction probability |
| Skew flips by horizon | Term-specific disagreement | Expiry-by-expiry rows | Do not average away conflict |
| Wings both rich | Convexity demand | Butterfly versus ATM | Can reflect supply conditions |
How should options skew be combined with other crypto data?
Compare skew with DVOL and realized volatility to separate relative wing pricing from the overall volatility level. Then check options expiry concentration: a nearby large expiry can make the front surface more event-sensitive.
Funding, OI and spot trend answer different questions. A downside-rich option surface alongside crowded long perpetuals is stronger context than either observation alone, but it remains an observation rather than a guaranteed trade.
How do I distinguish changing skew from a change in the selected option contracts?
Check the selected strikes, deltas and expiry at both observations. A nearest-25-delta selection can switch contracts as spot moves, producing a change partly due to selection rather than a uniform repricing.
Mark-based skew does not show an investor's actual hedge trade or guarantee executable option prices.
- Save selected put/call identifiers, delta distance and IV inputs.
- Compare the same expiry and sign convention before interpreting demand for downside or upside protection.
- Flag contract switches and missing quotes when creating a historical series.
Verify: Deribit public instruments · Deribit book summaries · CoinNudge methodology
What is measured, and what is not?
| Measured claim | Evidence on this page | Boundary |
|---|---|---|
| A selected downside or upside wing has richer Deribit mark IV. | Model-derived 25-delta call and put pair. | Selection depends on Black–Scholes assumptions and available strikes. |
| Skew differs across current expiries. | Separate 2-to-45-day rows. | The page does not interpolate a full volatility surface. |
| Wing pricing differs from ATM volatility. | Butterfly calculation using nearest-strike ATM IV. | Rich wings do not predict realized tails. |
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Method and data boundary
CoinNudge reuses Deribit's public instrument and book-summary responses. For each instrument, T is ACT/365 years from collection time to Deribit's expiration_timestamp, σ is mark_iv divided by 100 and r is that instrument's book-summary interest_rate. Delta uses d1=(ln(S/K)+(r+σ²/2)T)/(σ√T), call_delta=N(d1) and put_delta=N(d1)-1. The call closest to +0.25 and put closest to -0.25 are selected only when each is within 0.12 of target. The exact put, call and nearest-strike ATM instruments, rates, strikes, IVs and deltas are published. Skew equals put IV minus call IV; wing butterfly equals average wing IV minus ATM IV.
The 25-delta contracts are selected with a model-derived delta, not an exchange-supplied historical surface. Mark IV and OI are live Deribit observations; stale quotes, sparse strikes and model assumptions can affect selection. This is not option valuation, a historical percentile or a directional forecast.
Sources and verification
- Deribit public instrumentsOpen option definitions, strikes and expiries.
- Deribit book summariesMark IV, OI and underlying observations.
- CoinNudge methodologyDelta selection, staleness and missing-surface behavior.
Frequently asked questions
What is 25-delta skew?
The implied-volatility difference between comparable downside and upside option wings near 25 delta.
Why is positive skew associated with puts?
This page defines skew as put IV minus call IV, so a positive value means the put is richer.
Does positive skew predict a fall?
No. It describes current relative option pricing.
Where does delta come from?
CoinNudge calculates Black–Scholes delta from Deribit public inputs.
Why are some expiries missing?
A sufficiently close call-and-put delta pair or valid mark IV may not be available.
Is this a full volatility surface?
No. It is a reproducible selected-wing comparison across qualifying expiries.
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