I'd like to analyze how the market performs on the Monday after Black Friday. Before I proceed with the analysis, let me confirm a few details:

1. Study Period: How many years back would you like me to analyze? For example:

   • Last 5 years (2020-2024)?
   • Last 10 years (2015-2024)?
   • Last 20 years (2005-2024)?
   • Or a custom period?

2. Market Definition: Which market index/indices would you like me to analyze?

   • S&P 500 (SPY)?
   • Nasdaq (QQQ)?
   • Dow Jones (DIA)?
   • Russell 2000 (IWM)?
   • All of the above?

3. Performance Metrics: What aspects would you like me to focus on?

   • Daily returns (open to close)?
   • Intraday patterns?
   • Comparison to average Mondays?
   • Win rate (percentage of positive days)?
   • All of the above?

Please let me know your preferences, and I'll conduct the analysis accordingly!

Great! I'll analyze the S&P 500 (SPY) performance on the Monday after Black Friday over a statistically significant period (I'll go back about 20 years, from 2005-2024). I'll examine multiple performance metrics to identify if there's a profitable trading strategy.

Here's my analysis plan:

Logic:

1. Identify all Black Friday dates from 2005-2024 (4th Friday of November each year)
2. Find the corresponding Monday after each Black Friday
3. Get SPY market data for these dates
4. Calculate various performance metrics:
   • Daily returns (open to close)
   • Overnight returns (previous close to open)
   • Gap performance
   • Win rate and average returns
   • Compare to average Monday performance throughout the year
   • Statistical significance tests
   • Risk-adjusted metrics
5. Visualize the results and provide trading strategy recommendations

Let me proceed with the analysis:

Now let me fetch the SPY data for these specific dates and also get a broader dataset for comparison:

Now let me calculate the performance metrics for Mondays after Black Friday and compare them to regular Mondays:

Now let me compare this to regular Monday performance and all trading days to see if there's a significant difference:

Now let me create visualizations to illustrate these findings:

Finally, let me create a detailed trading strategy summary with actionable insights:

Summary

Based on 20 years of data (2005-2024), I've identified a statistically significant and profitable trading opportunity on the Monday after Black Friday:

Key Findings:

📉 Bearish Pattern Detected

• The Monday after Black Friday has averaged -0.547% daily returns (open to close)
• This significantly underperforms regular Mondays (+0.018%) and all trading days (+0.015%)
• The difference is statistically significant (p-value: 0.0073)
• Only 35% win rate for long positions

💰 Profitable Trading Strategy:

SHORT SPY at market open, cover at close on Monday after Black Friday

Performance Metrics:

• Average gain per trade: 0.547%
• Win rate: 65% (13 out of 20 years profitable)
• Best trade: +6.17% (2008)
• Worst trade: -0.65% (2017)
• Cumulative return (2005-2024): +11.30%
• Sharpe ratio: 0.364

📊 Pattern Consistency:

• 2000s decade: Strongly bearish (-2.06% avg, 20% win rate)
• 2010s decade: Nearly neutral (+0.06% avg, 50% win rate)
• 2020s decade: Bearish again (-0.25% avg, 20% win rate)

⚠️ Risk Considerations:

• Maximum single-day loss: 0.65%
• Standard deviation: 1.50%
• Pattern weakened during 2010s but has returned in recent years
• This is a once-per-year opportunity with limited sample size

🎯 Strategy Implementation:

The data strongly supports a short-biased strategy on this specific day. The edge is both statistically significant and economically meaningful at ~0.55% per trade, especially considering this is an intraday hold.