What Is Put-Call Parity?
Put-call parity is a fundamental principle in options pricing that defines the relationship between the price of a European call option and a European put option with the same strike price and expiration date. The formula states that: C + K × e^(-rT) = P + S, where C is the call price, P is the put price, K is the strike price, S is the underlying stock price, r is the risk-free interest rate, and T is the time to expiration in years.
When this relationship is violated — meaning one side of the equation is significantly higher than the other — it creates a theoretical arbitrage opportunity. Our free Put-Call Parity Arbitrage Detector scans real-time options chain data to identify these mispricings automatically, helping traders spot potential opportunities before they disappear.
Why Use Our Put-Call Parity Arbitrage Detector?
Automated Scanning
Automatically scans every call-put pair in the options chain to identify put-call parity violations. No manual calculations needed — just enter a ticker and scan.
Precise Parity Calculation
Uses the continuous-compounding put-call parity formula with configurable risk-free rate and transaction cost threshold to filter out noise and highlight genuine opportunities.
Direction & Profit Estimate
For each detected opportunity, see the recommended trade direction (buy underpriced, sell overpriced) and the estimated profit per contract before transaction costs.
Real-Time Market Data
Powered by live options chain snapshots with bid/ask quotes, volume, open interest, and implied volatility for every contract in the analysis.
Sortable Results Table
Sort arbitrage opportunities by mispricing amount, percentage, estimated profit, strike price, or volume to quickly find the most actionable trades.
Configurable Threshold
Set your own transaction cost threshold to filter out small mispricings that wouldn't be profitable after commissions, slippage, and execution costs.
How to Use This Put-Call Parity Arbitrage Detector
- 1
Enter a Ticker
Type any U.S. stock or ETF ticker symbol (e.g., AAPL, SPY, TSLA, MSFT) in the ticker field. Choose stocks with liquid options markets for the most meaningful results.
- 2
Set Expiration & Parameters
Select an expiration date to focus on specific contracts. Adjust the risk-free rate (default: current short-term Treasury yield) and the cost threshold to match your trading costs and risk tolerance.
- 3
Scan for Arbitrage
Click "Scan for Arbitrage" to fetch the options chain and run the put-call parity analysis. The tool pairs every call with its corresponding put at the same strike and expiration, then calculates the theoretical mispricing.
- 4
Analyze Opportunities
Review the results table showing each arbitrage opportunity with the trade direction, mispricing amount, estimated profit, and bid/ask spreads. Sort by any column to prioritize the most attractive opportunities.
Important Considerations
- American vs. European Options: Put-call parity strictly applies to European-style options. Most U.S. equity options are American-style, which means early exercise rights can cause small deviations from theoretical parity. This tool accounts for this by allowing you to set a cost threshold.
- Transaction Costs: Real-world arbitrage requires accounting for commissions, bid-ask spreads, margin requirements, and execution risk. Always verify that the detected mispricing exceeds your total round-trip costs.
- Dividends: Expected dividends before expiration can cause apparent parity violations. If the underlying stock pays a dividend before the option expires, the put-call parity relationship needs adjustment.
- Execution Speed: Options arbitrage opportunities are typically short-lived. By the time you identify and attempt to execute a trade, the mispricing may have already corrected. This tool is best used for educational purposes and market analysis.