Options Historical Data: Where Good Data Actually Comes From
Serious options backtesting requires serious data. The free options data available online (Yahoo Finance options chains, basic broker historical data) is typically inadequate for anything beyond illustrative examples. For strategies you intend to deploy with real money, data quality matters substantially.
The Problem With Free Data
Yahoo Finance options. Current chains only. No historical option prices. Fine for examining current pricing, useless for backtesting.
Broker historical data. Varies widely. Most retail brokers provide only limited options history (30 days to 1 year typically). Not enough for meaningful strategy research.
Free "options history" sites. Often incomplete, inconsistent, or inaccurate. End-of-day prices only, missing specific strikes, no bid-ask data.
For retail traders experimenting with ideas, free data is a reasonable starting point. For strategies you plan to deploy, inadequate.
Paid Data Sources
Polygon Options ($99-249/month). Mid-range option data. Trades, quotes, snapshots. Growing US options coverage. Good value for retail strategy development.
CBOE DataShop ($150-800/month depending on depth). Official CBOE options data. End-of-day products reasonable price; intraday products more expensive. The institutional standard.
IVolatility ($500+/month). Comprehensive options analytics plus historical data. Expensive but widely used by professional analysts.
ORATS ($189+/month). Options-focused data with pre-computed Greeks, implied volatility surfaces, and historical skew analysis.
Alpha Query ($20-100/month). Mid-tier options data. Reasonable for less demanding use cases.
For most retail options traders doing serious research, Polygon offers best value. Covers retail-relevant needs at reasonable price.
What Data Quality Means
Beyond just "having options data," specific quality dimensions:
Trade vs quote data. Actual trades show what prices actually filled. Quotes show what was offered. Both matter for backtesting.
Open interest history. Changes in open interest reveal strategy adoption and liquidity trends.
Greeks history. Delta, gamma, theta, vega at historical points in time. Important for strategies that condition on Greeks.
Implied volatility surface. Full term structure and skew, not just ATM IV.
Dividend adjustments. Options adjustment for dividends can affect historical analysis.
Early exercise adjustments. American options can be exercised early. Historical data should reflect assignment events.
Point-in-time data. The data that was available at each historical moment, not reconstructed with hindsight.
Not all paid data sources provide all quality dimensions. Review specific vendor documentation before purchase.
The Specific Quality Tiers
For retail options backtesting, three practical quality tiers:
Tier 1 (basic): Polygon end-of-day data. $99/month. Daily close prices for all strikes, limited intraday. Sufficient for most swing-trading strategies that don't require intraday execution analysis.
Tier 2 (intermediate): Polygon intraday data. $200-250/month. Minute-bar options prices. Sufficient for strategies with intraday entry/exit timing.
Tier 3 (serious): CBOE DataShop + IVolatility. $500-1500/month. Full historical depth, Greeks, surface analysis. For institutional-grade research.
Most retail traders should start at Tier 1. Upgrade only when specific research questions require more sophisticated data.
Historical Depth
How much history matters for backtesting:
5-10 years: minimum for strategies to see multiple market regimes.
15-20 years: better for strategies with longer cycle sensitivity.
20+ years: necessary for strategies claiming to work "across all market conditions."
Most paid vendors offer 10-20+ years. Verify specific instrument coverage — SPY options have more history than individual stock options, for example.
Alternative Approaches
If paid data budget is not available:
Reconstructed data from broker APIs. Some brokers (Interactive Brokers specifically) allow pulling historical option data via API. Rate-limited and incomplete but functional for specific experiments.
QuantConnect cloud platform. $20-200/month includes option data access through their platform. Does not export, but allows backtesting in cloud.
OptionsMetrics / academic. Some university programs provide access to IvyDB for academic research.
Collaborative data. Trading communities sometimes share aggregated data. Legal and quality considerations vary.
For serious retail options research, there is no good way to avoid paying for data if you want sufficient quality.
Practical Framework
For strategy illustration and learning: free data is fine. Yahoo Finance current chains, broker's limited history.
For strategy prototyping: Polygon basic ($99/month). Enough to validate ideas have genuine edge.
For strategy deployment research: Polygon intraday or CBOE DataShop. Clean enough to make real money decisions.
For institutional-grade research: full IVolatility + proprietary data pipeline. Not needed for retail scale.
The data quality step from free to Polygon basic is dramatic. The step from Polygon basic to CBOE DataShop is incremental. Diminishing returns beyond mid-tier for retail use.
Serious options backtesting is a serious endeavor. Treating data as a cost center that must be minimized leads to backtests that cannot be trusted. Treating data as an infrastructure investment that enables good research produces much better outcomes.
