The Overnight Edge: How QQQ's Recent Weekday Patterns Reveal a Surprising Trading Strategy

Introduction

What if the best trading strategy over the past six months was simply to buy at the close and sell at the open?

We analyzed 125 trading days of QQQ (NASDAQ-100 ETF) data from June 3, 2025 through November 28, 2025, and the results are striking. In this article, we break down the performance by weekday and time period, revealing patterns that challenge conventional wisdom about when and how to trade.

The Big Picture: Overnight vs. Intraday

Before diving into the day-by-day breakdown, let's look at the cumulative performance of two simple strategies:

Intraday Strategy: Buy at the open, sell at the close (capture the trading day)

Overnight Strategy: Buy at the close, sell at the next open (capture the gap)

Starting with $100 on June 3, 2025:

• Intraday Final Equity: $97.39 (Total Return: -2.61%)
• Overnight Final Equity: $121.53 (Total Return: +21.53%)

That's a 24 percentage point difference over just six months. The overnight strategy returned over 21% while the intraday strategy actually lost money.

This pattern isn't unique to this period—academic research has documented the "overnight return premium" for decades. But the magnitude we're seeing in recent months is particularly pronounced.

Intraday Returns by Weekday

Let's break down how QQQ performed during regular trading hours (9:30 AM to 4:00 PM ET) for each day of the week:

Monday: The Standout Performer

Monday emerged as the clear winner for intraday trading with a 70.8% win rate and an average return of +0.308% per session. This is significantly higher than any other day.

• Bull Average: +0.535% (when the day was positive)
• Bear Average: -0.243% (when the day was negative)
• Sample Size: 24 Mondays

The asymmetry here is notable: positive Mondays averaged more than double the magnitude of negative Mondays. This suggests that when Monday is up, it tends to be up convincingly.

Thursday: The Weakest Link

Thursday was the worst day for intraday trading with a 45.8% win rate and an average return of -0.329% per session.

• Bull Average: +0.472% (when the day was positive)
• Bear Average: -1.006% (when the day was negative)
• Sample Size: 24 Thursdays

The bear average of -1.006% is particularly concerning—negative Thursdays tend to be severe. This day has been characterized by significant down moves.

The Complete Intraday Picture

Here's the full breakdown ranked by average return:

1. Monday: +0.308% avg, 70.8% win rate

2. Wednesday: +0.070% avg, 53.8% win rate

3. Tuesday: -0.066% avg, 46.2% win rate

4. Friday: -0.074% avg, 56.0% win rate

5. Thursday: -0.329% avg, 45.8% win rate

Notice that only Monday has a win rate above 55%. The other days hover around 50% or below, suggesting intraday price action has been essentially a coin flip—or worse.

Overnight Returns by Transition

Now let's examine what happened between the close and the next open:

Friday→Monday: The Weekend Premium

The transition from Friday's close to Monday's open showed the strongest overnight returns with a 73.9% win rate and an average gap of +0.452%.

• Bull Average: +0.680% (when the gap was positive)
• Bear Average: -0.193% (when the gap was negative)
• Sample Size: 23 weekends

Nearly three-quarters of weekends saw the market gap higher on Monday. The average positive gap (+0.680%) was 3.5x larger than the average negative gap (-0.193%).

Tuesday→Wednesday: The Mid-Week Sweet Spot

The Tuesday close to Wednesday open transition also performed exceptionally well with a 73.1% win rate and an average gap of +0.210%.

• Bull Average: +0.354%
• Bear Average: -0.180%
• Sample Size: 26 transitions

The Complete Overnight Picture

Here's the full breakdown ranked by average return:

1. Friday→Monday: +0.452% avg, 73.9% win rate

2. Wednesday→Thursday: +0.211% avg, 66.7% win rate

3. Tuesday→Wednesday: +0.210% avg, 73.1% win rate

4. Thursday→Friday: +0.034% avg, 60.9% win rate

5. Monday→Tuesday: -0.033% avg, 60.0% win rate

Every overnight transition had a win rate of 60% or higher. The worst overnight transition (Monday→Tuesday) still outperformed the best intraday session in terms of consistency.

Why This Pattern May Exist

Several factors may contribute to the overnight premium we've observed:

1. Institutional positioning: Large institutions often accumulate positions after hours to avoid moving the market during the trading day.

2. Positive news timing: Corporate earnings and economic data are often released before the market opens, and companies tend to time positive announcements strategically.

3. Short covering: Short sellers who don't want to hold overnight risk contribute buying pressure at the close.

4. Global markets: Overnight gains may reflect positive price action in Asian and European markets.

5. Fear of missing out: After market hours, retail investors can place orders that execute at the open, often creating buying pressure.

Practical Implications

For Day Traders

The data suggests being selective about which days to trade:

• Monday offers the best intraday opportunities
• Thursday should be approached with caution or avoided entirely
• Overall, intraday strategies have faced a challenging environment

For Swing Traders

If you're comfortable holding overnight:

• The weekend gap (Friday close → Monday open) has been particularly profitable
• Mid-week overnight holds have also performed well
• The overnight premium is real and has been significant

For Long-Term Investors

This data reinforces that time in the market matters more than timing the market. Most gains have occurred outside of trading hours, which means market orders at the open capture much of the value.

Important Caveats

Before implementing any strategy based on this analysis:

1. Sample size: 125 trading days is meaningful but not definitive. Patterns can and do change.

2. Transaction costs: Frequent trading incurs commissions and slippage that can erode returns.

3. Execution risk: Buying at the close and selling at the open sounds simple, but execution can be challenging.

4. Past performance: These patterns reflect the recent past, not necessarily the future.

5. Market regime: The period analyzed (June-November 2025) had specific characteristics that may not persist.

Conclusion

The last 180 days of QQQ trading data reveal a striking pattern: overnight returns have dramatically outpaced intraday returns. The simple strategy of buying at the close and selling at the open would have returned over 21%, while buying at the open and selling at the close would have lost money.

Among weekdays, Monday stands out as the best day for intraday trading, while Thursday has been the worst. For overnight holds, the weekend gap from Friday to Monday has been particularly lucrative.

Whether these patterns persist remains to be seen. But the data suggests that for those who can tolerate overnight risk, there may be an edge worth exploring.

For more detailed weekday analysis with interactive charts, visit our Weekday Analysis page where you can filter by different time periods and explore these patterns yourself.

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Data source: QQQ (NASDAQ-100 ETF) daily OHLC prices. Analysis period: June 3, 2025 - November 28, 2025. This article is for educational purposes only and does not constitute investment advice.