Implied Volatility Surface
Explore implied volatility across strikes and expirations. Spot skew anomalies, term structure shifts, and relative value opportunities in real time.
IV heatmap from live market data. Free with any account. SVI-fitted surface with Gatheral parameterization available on the Alpha plan.
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IV Heatmap - Expiration vs Strike
| Expiry \ Strike | |
|---|---|
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SVI Volatility Surface
AlphaGatheral SVI-fitted implied volatility. Compare market IV vs SVI-smoothed IV to spot mispricings.
SVI-Calibrated Volatility Surface
Gatheral's SVI parametric fit produces smooth, arbitrage-free implied volatility across every strike and expiry. Spot mispricings between raw market IV and SVI-smoothed IV, build production-grade vol surfaces, and compute stable Greeks for OTM and illiquid contracts.
SVI-Fitted IV by Strike & Expiration
| Expiry \ Strike | |
|---|---|
IV vs SVI Deviation (market IV - SVI fit)
Positive = market IV above SVI fit (potentially overpriced). Negative = below fit (potentially underpriced).
| Expiry \ Strike | |
|---|---|
ATM IV Term Structure
25-Delta Risk Reversal
Put 25d IV - Call 25d IV. Positive = put skew dominates.
Richest Contracts (IV > SVI)
| Contract | IV | SVI | Dev | OI |
|---|---|---|---|---|
Cheapest Contracts (IV < SVI)
| Contract | IV | SVI | Dev | OI |
|---|---|---|---|---|
Put/Call Skew by Expiration
| Expiry | Put 25d IV | ATM IV | Call 25d IV | Skew (P-C) |
|---|---|---|---|---|
IV Smile (Market IV vs SVI Fit)
| Strike | Market IV | SVI IV | Diff | OI | Deviation |
|---|---|---|---|---|---|
|
|
OI-Weighted IV by Expiration
IV weighted by open interest - shows where real positioning concentrates.
What can you do with the Vol Surface?
The SVI $\rho$ parameter directly captures put/call skew. Visualize how the smile rotates across expirations - steep near-term skew flattening into longer tenors is classic equity behavior.
Compare ATM variance ($a$ parameter) across tenors. Spot backwardation (near > far) or contango (far > near) to gauge market fear, event pricing, and calendar spread opportunities.
SVI enforces no-butterfly-arbitrage constraints. Compare raw market IV against the SVI fit - deviations signal potential mispricings or unusual positioning at specific strike/expiry nodes.
Get this via API
curl https://lab.flashalpha.com/v1/surface/SPYimport requests
r = requests.get(
"https://lab.flashalpha.com/v1/surface/SPY"
)
data = r.json()
print(f"Grid size: {data.get('grid_size')}")
print(f"IV shape: {len(data.get('iv', []))} tenors")Explore more tools
The SVI volatility surface is included with every plan. Want more? Explore GEX, DEX, VEX, and CHEX tools - all available with your free API key.
See All ToolsUnderstanding the SVI Volatility Surface
The implied volatility surface is a three-dimensional mapping of option-implied volatility as a function of strike price (or moneyness) and time to expiration. Rather than displaying raw market quotes - which are noisy, sparse, and often arbitrageable - FlashAlpha fits the surface using Gatheral's Stochastic Volatility Inspired (SVI) parameterization, the industry standard for smooth, arbitrage-free vol surface construction.
What is SVI?
The SVI model, introduced by Jim Gatheral in "The Volatility Surface: A Practitioner's Guide" (2006), parameterizes the total implied variance $w(k)$ as a function of log-moneyness $k = \ln(K/F)$:
The Five SVI Parameters
Each parameter has a clear financial interpretation, making SVI uniquely intuitive among parametric vol models:
- $a$ - Overall variance level. Controls the vertical position of the smile.
- $b$ - Wing slope. Determines how steeply IV rises for deep OTM puts and calls. Must satisfy $b \geq 0$.
- $\rho$ - Rotation (skew). Captures the asymmetry between put and call wings. In equities, $\rho < 0$ reflects downside skew.
- $m$ - Translation. Shifts the smile's center left or right along the moneyness axis.
- $\sigma$ - Smoothness. Controls the curvature of the ATM region. Larger $\sigma$ produces a wider, flatter trough.
Why SVI Over Raw IV?
Raw implied volatilities from option quotes are noisy - bid-ask spreads, stale quotes, and illiquid strikes create gaps and inconsistencies. SVI addresses this by:
- Smoothing - producing a continuous surface from discrete market quotes
- Interpolation - estimating IV for strikes with no active market
- Arbitrage constraints - ensuring the surface satisfies no-butterfly-arbitrage conditions ($\partial^2 C / \partial K^2 \geq 0$)
- Extrapolation - extending the surface to deep OTM regions with controlled wing behavior
The Volatility Smile and Skew
In equity markets, OTM puts consistently trade at higher implied volatility than OTM calls - the "skew." This reflects demand for downside protection and the empirical observation that markets crash more than they rally. The SVI $\rho$ parameter directly captures this asymmetry. The skew steepens for near-dated options and flattens for longer maturities.
Term Structure
The term structure of volatility shows how ATM IV changes across expirations. In the SVI framework, the $a$ parameter (variance level) evolves across tenors:
- Contango (normal) - far-dated IV > near-dated IV. Markets expect mean reversion.
- Backwardation (inverted) - near-dated IV > far-dated IV. Elevated near-term fear, often around earnings, FOMC, or selloffs.
Reading the Heatmap
Each cell in the heatmap shows the SVI-fitted implied volatility for a specific strike-expiration node. Color intensity indicates IV level:
- Green - low IV, relatively cheap options
- Yellow - moderate IV, fair value
- Red - high IV, expensive options or elevated fear
Look for anomalies: cells where raw market IV deviates significantly from the SVI fit may indicate mispricing, unusual positioning, or event-driven dislocations at that strike/expiry.
SVI Calibration Method
FlashAlpha calibrates SVI parameters per tenor slice using a weighted least-squares fit to mid-market implied volatilities, with higher weight on liquid ATM/near-money strikes. The calibration enforces:
- $a + b\sigma\sqrt{1-\rho^2} \geq 0$ (non-negative variance)
- $b \geq 0$ (non-negative slope)
- $|\rho| < 1$ (valid correlation)
- $\sigma > 0$ (positive smoothness)
Limitations
- Parametric shape - SVI imposes a specific functional form. Real market IV may exhibit features (e.g., kinks from large open interest at specific strikes) that SVI cannot capture.
- Per-slice calibration - each tenor is fit independently. Cross-tenor arbitrage is not guaranteed without an additional SSVI or eSSVI layer.
- Snapshot data - the surface reflects a point-in-time snapshot of mid-market IVs. It updates periodically, not tick-by-tick.
- Not a trading signal - the surface describes the market's pricing, not its direction. Use it for context, not as a standalone signal.