do stocks usually go down on mondays?

Do stocks usually go down on Mondays?

When investors ask “do stocks usually go down on mondays” they are referring to the historical puzzle called the "Monday effect" or "weekend effect": the observation in some datasets that stock returns on Mondays tend to be lower than returns on the preceding Fridays or other weekdays. This article explains what the phrase means, reviews historical discovery and empirical evidence, surveys proposed explanations, discusses whether the effect can be traded, compares equities with 24/7 markets such as crypto, and offers practical takeaways for ordinary investors.

As of 2026-01-22, according to Investopedia and other market commentators, the empirical evidence is mixed: the Monday effect has appeared in some historical windows and samples but has weakened or disappeared at other times. The observed differences are typically small relative to transaction costs, and the effect varies by period, market segment, and methodology.

HIGHLIGHT: If you came here wondering do stocks usually go down on mondays, this article will help you understand the phenomenon, its possible causes, and why it rarely offers a simple trading edge for most investors.

Definition and terminology

The "Monday effect" (also called the "weekend effect") is a calendar anomaly in which average stock returns on Monday are lower than returns on other weekdays — sometimes lower than returns on the prior Friday in particular.

• Two related claims appear in commentary:
  • Claim A: Monday returns tend to follow or reverse the prior Friday’s trend (paired Friday–Monday comparison).
  • Claim B: Mondays are systematically worse than other weekdays on average (weekday comparison).

Both claims are used in market commentary, but they are conceptually distinct. Claim A focuses on the immediate two-day sequence and whether Friday gains are followed by weaker performance on the next trading day. Claim B treats Monday as one element of a weekday pattern and compares mean returns across Monday, Tuesday, Wednesday, Thursday and Friday.

Common synonyms and related phrases used in financial media and research include "weekend effect," "weekday effect," "day-of-week anomaly," and "Monday reversal."

If you are asking do stocks usually go down on mondays, be aware the phrase may be used to refer to either of the two claims above; precise testing depends on which definition a researcher chooses.

Historical discovery and early evidence

The Monday/weekend effect entered the academic literature in the early 1970s when researchers examined day-of-week patterns in exchange-listed stocks. Notably, Frank Cross published a finding that Friday gains were often followed by weaker returns on Monday — an observation that helped popularize the idea of a consistent Monday weakness.

Early empirical work concentrated on large, consolidated U.S. equity markets (NYSE and S&P-related data) and often used paired Friday–Monday comparisons. These early studies reported statistically significant negative Monday returns in many samples, which sparked interest from academics and practitioners seeking calendar-based trading rules.

It is important to stress that the earliest evidence was based on the market structure and information flows of its time: trading was more concentrated during trading hours, price discovery was slower, and many retail and institutional investors did not react to news during weekends as they might today.

Empirical evidence — what studies and data show

When readers ask do stocks usually go down on mondays, they expect a clear empirical answer. The truth is nuanced.

• Mixed results across periods: Major summaries and financial media note that some historical periods show negative average Monday returns relative to Fridays or to other weekdays. Other periods — notably parts of the late 1980s to late 1990s and beyond — show the pattern weakening or disappearing. The effect is not stable across decades.

• Small magnitudes: Where a Monday effect is reported, the average difference in returns is usually small — often measured in basis points to a few tenths of a percent. Such magnitudes are modest relative to trading costs, taxes, and normal market volatility.

• Sensitivity to sample choice: Results depend heavily on the index, exchange, country, sample period, and whether researchers control for confounding factors (e.g., volatility clustering, macro announcements, or seasonal effects). Some indices and small-cap universes show stronger patterns than large-cap indexes.

• Media and research summaries: Financial explainers and compilations from market outlets provide high-level summaries of these mixed findings. They typically emphasize that the Monday effect used to be clearer in earlier historical windows and that it has diminished in many modern samples.

• Statistical versus economic significance: Even when Monday differences are statistically significant, they are often not economically profitable once transaction costs (commissions, bid-ask spread), slippage, and taxes are considered.

In short, empirical studies offer evidence that the Monday effect has appeared at times but is inconsistent and often small.

Proposed explanations

Researchers and market commentators propose several mechanisms that could produce weekend-to-Monday return differences. None alone explains every observation, and plausibility can vary with time and market structure.

• Weekend news and information lag

  • Theory: Important corporate or macroeconomic information that arrives between Friday’s close and Monday’s open can cause price adjustments concentrated on Monday. If bad news more often arrives over weekends (or is perceived as more impactful when digested on Monday), average Monday returns could be lower.
  • Comment: With faster 24/7 news and mobile alerts today, the information-lag story is weaker than it was decades ago, but timing and interpretation of weekend developments can still concentrate trading on Monday.

• Short selling and trading mechanics

  • Theory: Short sellers may position over the weekend differently than long investors due to financing/timing constraints or availability of borrow. Liquidity constraints and short-selling costs can interact with the timing of short positions and Monday price moves.
  • Comment: Market regulation and changes in short-sale practices have evolved, altering how mechanically this explanation applies.

• Investor sentiment and behavioral factors

  • Theory: Behavioral explanations propose that investor mood, framing, or decision timing over weekends affects orders placed on Monday. For example, some investors delay decisions until the start of the week, producing a flow imbalance.
  • Comment: Behavioral channels are hard to measure, but they remain plausible contributors in some contexts.

• Liquidity and institutional flows

  • Theory: Lower pre-market and early-session liquidity on Mondays can amplify price moves. Institutional schedule-driven flows (e.g., portfolio rebalancing, mutual fund subscriptions/redemptions) concentrated at week-start can also create predictable pressure.
  • Comment: Larger-cap and highly liquid stocks are less affected by liquidity-driven anomalies than small caps.

Each proposed explanation can contribute in certain samples; the relative importance likely changes with market structure and information technology.

Market structure, time variation, and cross-sectional differences

If your central question is do stocks usually go down on mondays across markets and time, appreciate that the effect is neither stable nor universal.

• Time variation

  • The Monday/weekend effect has come and gone across different historical windows.
  • Structural changes — such as electronic trading, extended trading hours, faster news distribution, and algorithmic/liquidity provision improvements — tend to reduce simple calendar anomalies.

• Cross-sectional differences

  • Size and liquidity: Research often finds stronger day-of-week patterns in small-cap, less-liquid stocks than in large-cap, highly traded names.
  • Sector differences: Some sectors may react differently to weekend macro events (for example, cyclical sectors vs. defensive sectors), creating heterogeneity.

• International and asset-class differences

  • The pattern found in U.S. equities does not necessarily replicate in other countries or asset classes. Trading calendars, settlement rules, and local news cycles matter.
  • For fixed income, commodities, or foreign markets the calendar effects can differ substantially.

These cross-sectional differences are a key reason why the headline question do stocks usually go down on mondays lacks a single universal answer.

The Monday effect in modern practice — can it be traded?

Many readers who ask do stocks usually go down on mondays are wondering if they can profit from the pattern. Practical hurdles limit straightforward exploitation.

• Small economic magnitude

  • Average Monday differences are typically modest (basis points to a few tenths of a percent), so gross returns before costs look small.

• Trading costs and slippage

  • Bid–ask spreads, commissions, market impact, and taxes can erase the thin margin implied by the anomaly.

• Timing and execution risks

  • Pair trades or short-term timing strategies require reliable execution at predictable prices. Volatility and liquidity changes around market open can increase slippage.

• Regime dependence

  • Because the effect varies across samples and eras, a historically observed edge may evaporate once exploited by many participants.

• Institutional guidance

  • Many brokers and investor education pieces caution against day-of-week timing. They often encourage systematic, long-term approaches such as dollar-cost averaging rather than trying to trade small calendar anomalies.

• Day-trader vs. long-term investor perspective

  • For long-term investors, week-to-week day-of-week variation is noise relative to long-run return drivers (earnings, valuations, macro fundamentals). For active day traders, intraday patterns and liquidity dynamics matter more than cross-day average Monday weakness.

Overall, while do stocks usually go down on mondays can be answered with sometimes-yes historically, exploiting that information in live trading is often impractical.

Comparison with 24/7 markets (cryptocurrencies)

Cryptocurrency markets operate 24/7, which changes how weekday/ weekend calendar effects appear.

• No single "Monday open"

  • In continuous markets there is no clean weekend closure-to-Monday-open gap. That eliminates a mechanical source of Monday-specific jumps tied to market closures.

• Calendar patterns can still exist

  • Behavioral and liquidity cycles (e.g., retail activity on weekends vs. weekdays) and timing of announcements can still create calendar patterns in crypto, but the drivers and timing differ from U.S. equity weekend effects.

• Separate empirical study needed

  • If you are comparing equities and crypto, you should not assume the same calendar anomalies apply. Crypto researchers analyze hourly and daily patterns across continuous time to detect analogous effects.

If you hold both equities and crypto and ask do stocks usually go down on mondays as a guide for crypto, be cautious: continuous trading changes the mechanics and often the empirical results.

Note: when discussing trading venues and wallets for crypto and web3, Bitget is one of the platforms that offers continuous trading and portfolio services; for on-chain custody and wallet features, Bitget Wallet is recommended for integration with Bitget services.

Methodology and research considerations

When reading studies or media pieces that address do stocks usually go down on mondays, check how the analysis was done. Common research designs include:

• Paired Friday–Monday comparison

  • Researchers compute returns from Friday close to Monday close (or Monday open) and compare them to Friday returns, testing whether mean differences are negative.

• Weekday-average comparison

  • Comparing mean returns across all weekdays, often using ANOVA or similar tests, to detect systematic differences.

• Controls and robustness checks

  • Controlling for volatility, macro announcements, turn-of-month effects, and seasonal patterns is important. Researchers may exclude days with major macro events or earnings releases to see whether the effect persists.

Statistical and measurement caveats:

• Sample selection and survivorship bias

  • Studies excluding delisted firms or using convenience samples can produce biased estimates.

• Structural breaks and changing market conditions

  • The presence of structural breaks (e.g., introduction of electronic trading) can change the underlying process that generated earlier anomalies.

• Data-snooping and multiple hypothesis testing

  • With many possible calendar anomalies to test, some findings may arise by chance if proper corrections are not applied.

Careful empirical work will report effect sizes, confidence intervals, and robustness to alternative specifications.

Criticisms and limitations of the Monday-effect literature

The Monday-effect literature faces several critiques that help explain why the phenomenon is treated cautiously:

• Inconsistency across time and markets

  • The effect is not persistent across all periods or markets, which undermines claims of a universal anomaly.

• Small effect sizes

  • Even where statistically significant, the small magnitude limits practical value.

• Transaction costs and market friction

  • Any profitable pattern must survive realistic implementation costs.

• Potential for data artifacts

  • Specific sample choices, data-cleaning practices, and unreported robustness checks can produce artifactual findings.

• Changing market structure

  • As trading and information transmission evolve, simple calendar effects may weaken or vanish.

Researchers and practitioners therefore treat the Monday effect as an interesting historical pattern that requires careful scrutiny rather than a reliable trading rule.

Practical takeaways

If your practical question is do stocks usually go down on mondays and how you should act, here are concise, practical points:

• Empirical answer: The Monday effect has been observed at times, but its presence is inconsistent and the average magnitude is small.

• Trading implication: The anomaly is rarely robust enough to be profitably traded after realistic costs.

• Investor guidance: Most long-term investors should not base buy/sell decisions on weekday timing alone. Instead, consider fundamentals, diversification, and long-term plans.

• If you trade actively: Test any day-of-week strategy on your target universe, account for execution costs, and use out-of-sample validation before risking capital.

• For crypto or 24/7 markets: Do not assume equity calendar effects transfer directly. Study continuous-time patterns specifically.

• Tools and platforms: If you need reliable execution or custody, consider using reputable trading platforms and wallets. For integrated trading and custody solutions, Bitget and Bitget Wallet are options to explore for efficient order routing and continuous-market access.

These takeaways reflect academic caution and practical implementation realities; nothing here is investment advice.

Related calendar anomalies

Calendar anomalies often discussed alongside the Monday effect include:

• Day-of-week effects (beyond Monday to include other weekday patterns)
• Turn-of-the-month effect (abnormally high returns around the start of a month)
• Month-of-year / January effect (historically higher returns in January)
• Pre- and post-holiday effects (returns around market holidays can differ)

These anomalies may interact with or confound Monday/weekend observations, and many require the same careful scrutiny and robustness testing.

See also

• Monday effect
• Weekend effect
• Day-of-week effect
• Calendar anomalies
• Market microstructure
• Behavioral finance

References and further reading

As of 2026-01-22, the following sources summarize historical findings and provide further detail (listed as titles and outlets):

• What Is the Monday Effect on Stock Market Prices? — Investopedia (article)
• Understanding the Weekend Effect in Stock Markets — Investopedia (article)
• What Is the Monday Effect? — The Motley Fool (article)
• Why Day-of-the-Week Investing Is Ineffective — Chase insights (article)
• What’s the best time of the week to buy and sell shares? — IG (overview)
• Best Times of the Day, Week, and Month to Trade Stocks — Investopedia (guide)
• What Is the Monday Effect and How Does It Impact Stock Prices? — AccountingInsights (explainers)
• Theory Says Don't Sell Your Investments on Monday — Yahoo Finance summary (news)
• How to Know When to Buy a Stock — SoFi (background on timing)

Notes on reporting dates: As of 2026-01-22, according to Investopedia and The Motley Fool, researchers emphasize that the Monday/weekend effect has weakened in many modern samples, and any remaining differences are generally small.

Final notes and next steps

If you came here asking do stocks usually go down on mondays to decide how to trade this week, remember the empirical pattern is mixed and often too small to overcome trading costs. A practical path for most investors is to focus on diversified, systematic plans rather than short-term weekday timing.

If you want to explore execution, custody, or continuous-market access while testing calendar strategies, consider evaluating trading platforms and wallets. Bitget provides trading services and Bitget Wallet supports custody and web3 interaction; investigate platform features, fees, and execution quality in a demo or paper-trading environment before applying real capital.

Explore more about market anomalies, test ideas with out-of-sample data, and keep in mind that changing market structure can alter historical patterns.

(Call to action) To learn more about trading infrastructure and custody solutions that can support research and execution, explore Bitget services and Bitget Wallet documentation and demo tools.