Common Behavioural Biases That Affect Mutual Fund Investments

Behavioural biases quietly cost mutual fund investors far more than expense ratios ever will. They show up as stopping SIPs at the worst possible time, chasing last year’s winners, or sitting in underperforming funds for years because “it will come back”. Studies on Indian investors repeatedly find that emotions and mental shortcuts drive a large part of mutual fund decisions, often leading to lower real-life returns than what the funds themselves deliver.

Understanding these biases is half the battle. Once you can name them, you can design simple systems to keep them from derailing your mutual fund journey.

What are behavioural biases in mutual fund investing?

Behavioural biases are predictable psychological patterns that push investors away from rational, data-based decisions. Instead of calmly following a plan, investors react to recent headlines, friends’ opinions, fear, or overconfidence.

Research on Indian investors highlights loss aversion, overconfidence, herd mentality, and mental accounting as particularly strong influences on investment decisions and portfolio outcomes. These biases don’t just affect which funds people buy; they also shape when they enter, exit, switch, and stop SIPs.

Bias 1: Loss aversion - fear of losing beats the joy of gaining

Loss aversion means losses feel far more painful than equivalent gains feel good. A 10 percent fall in your mutual fund NAV can feel emotionally worse than a 10 percent gain feels satisfying.

In practical terms, loss aversion leads to:

• Stopping SIPs or redeeming equity funds in a correction, even when long-term data shows that investing during dips often improves returns.

• Holding on to losing schemes too long, hoping to “just get back to cost”, instead of objectively reviewing whether the fund still fits your strategy.

A recent behavioural study found that around 70 percent of investors showed strong loss-aversion tendencies, making them reluctant to book losses or invest more when markets are down. Industry data also shows SIP stoppages rise as volatility rises, despite the fact that rupee-cost averaging is most powerful in down markets.

How to fight it:

• Decide in advance what role each fund plays (large-cap core, mid-cap satellite, debt stabiliser) and what would trigger a change.

• During corrections, focus on your time horizon (5–10 years for equity funds) and not on 3–6 month NAV moves.

  
  

Bias 2: Herd mentality – doing what “everyone” seems to be doing

Herd mentality shows up when investors choose funds because “everyone is buying this new fund” or “my colleague doubled money in that small-cap scheme”. Instead of research, the decision is driven by social proof and fear of missing out.

For mutual fund investors, this leads to:

• Chasing the latest “hot” category (for example, small- and mid-cap funds after a big rally), often entering near peaks.

• Ignoring whether the fund’s risk profile, volatility and drawdown history match their own goals and risk appetite.

Studies suggest that a small minority of “informed” investors or influencers can sway the decisions of a large majority, which is why trends, WhatsApp tips and social media narratives can create bandwagon effects. In India, research on stock market volatility also finds clear evidence of herding among retail investors during sharp moves.

How to fight it:

• Start with your goals (timeline and amount), then pick categories and funds. Don’t start with a product.

• If the main reason you like a fund is “everyone is talking about it”, treat that as a red flag and dig deeper.

  
  

Bias 3: Overconfidence – overestimating one’s skill and knowledge

Overconfidence is the belief that you can “outsmart the market” or pick the next multi-bagger fund, often without a solid process to back that belief.

Research on behavioural finance shows that about 60 percent of investors display strong overconfidence, leading to excessive trading and risk-taking. Indian studies also find that overconfident investors trade more around volatility spikes, contributing to market swings.

In mutual funds, overconfidence typically causes:

• Frequent switching between schemes based on recent 6–12 month performance.

• Building cluttered portfolios with 10–20 overlapping funds because “more is better”, when in reality the portfolio behaves like an expensive index.

The impact is clear in holding-period data. In India, many equity mutual fund investors stay invested for barely 2–3 years, even though advisers recommend a 5–7 year view; this behaviour cuts off the compounding that shows up strongly only after a decade.

How to fight it:

• Limit portfolio churn. Review annually; act only if there is a clear, data-backed reason.

• Keep your core simple: a couple of well-chosen diversified funds can do more than a dozen schemes picked on gut feel.

  
  

Bias 4: Anchoring – getting stuck to a reference point

Anchoring happens when you fixate on a specific number or past outcome and allow it to drive all future decisions. In mutual funds, this could be:

• Clinging to a fund because it once gave stellar returns, even if it has lagged its category for years.

• Refusing to invest because “Nifty used to be at 15,000, now it’s 22,000; it’s too high”, instead of looking at valuations and future earnings.

AMCs and research platforms point out that investors often stick to schemes based on one great year and ignore several subsequent years of underperformance, a classic case of anchoring on a single data point.

How to fight it:

• When reviewing a fund, look at rolling returns, consistency vs benchmark, and risk metrics over multiple years, not one impressive period.

• Ask: “If I did not already own this fund, would I buy it today?” If the honest answer is no, anchoring might be at work.

  
  

Bias 5: Mental accounting – treating money differently based on labels

Mental accounting is the tendency to create different “buckets” in our heads for money, and then treat each bucket differently.

For mutual fund investors, this can look like:

• Taking excessive risk with a “bonus” or “extra” amount while being ultra-conservative with salary savings, even though both contribute to the same goal.

• Keeping random small SIPs going in multiple old schemes just because “it’s only ₹1,000”, instead of consolidating and aligning them with actual goals.

Studies on Indian investors show that around half exhibit strong mental accounting tendencies, which leads to scattered portfolios and inconsistent risk-taking across buckets.

How to fight it:

• Map every SIP to a goal (retirement, child’s education, house down payment) and a time horizon. Money doesn’t care about its source, only about how it’s deployed.

• Periodically clean up: close “legacy” funds that don’t fit your plan and redirect those SIPs into your core portfolio.

  
  

Bias 6: Recency bias and disposition effect – overreacting to the latest performance

Recency bias is giving too much weight to recent events, while the disposition effect is the tendency to sell winners too early and hold losers too long. Both are heavily visible in mutual fund behaviour.

Evidence from NSE’s Market Pulse and other behavioural studies shows:

• Investors quickly pour money into funds or categories that have done well over the last 1–3 years, often just as the cycle is turning.

• There is a tendency to book profits in funds that have done well recently while stubbornly holding on to underperforming schemes hoping they will “catch up”, hurting long-term portfolio returns.

This short-termism is also reflected in average holding periods of less than five years for many Indian equity funds, even though wealth from compounding really accelerates beyond the 10–15 year mark.

How to fight it:

• When evaluating performance, use longer horizons and rolling return data rather than only 1-year trailing returns.

• Have predefined rules for when you will exit a laggard fund (for example, consistent underperformance vs category and benchmark over 3 years), instead of reacting emotionally.

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Bias 7: Regret aversion – decisions driven by fear of future regret

Regret aversion means avoiding actions that might later make you say, “I should not have done that,” even if those actions are rational today.

In mutual funds, this can show up as:

• Sticking with only debt funds or FDs to avoid the regret of a potential equity market crash, even if your goals are 15–20 years away.

• Avoiding necessary portfolio rebalancing because you “don’t want to be wrong” if markets move against you immediately after the switch.

Over time, regret aversion can cause chronic underperformance versus what your plan could have achieved if implemented fully.

How to fight it:

• Focus on process, not outcomes. A well-thought-out asset allocation implemented consistently is “right” even if 1–2 year returns are not spectacular.

• Automate decisions like SIPs and annual rebalancing so they don’t feel like big “yes/no” calls each time.

  
  

Putting it all together: designing bias-proof mutual fund behaviour

Biases are part of being human. The goal is not to eliminate them, but to build a mutual fund investing framework that reduces their impact.

Practical guardrails that help:

• Write down your goals, time horizons and required return range. Use this to decide how much goes into equity, debt and other assets, instead of deciding based on moods or market levels.

• Limit portfolio complexity. A focused set of 4–6 mutual funds across equity, hybrid and debt often does the job; more schemes rarely mean better diversification.

• Automate via SIPs and STPs, especially during volatile markets, so rupee-cost averaging works in your favour rather than emotions forcing you to chase rallies or fear crashes.

• Review once or twice a year with clear metrics and, if needed, a qualified adviser. Reacting weekly to NAV moves is a sure way to feed your biases.

With over ₹43 lakh crore of Indian household wealth now in mutual funds, even small improvements in investor behaviour can translate into massive long-term gains. Recognising your own biases is the first and most powerful step toward reducing the behavioural gap in investing and improving long-term mutual fund returns.

FAQs on behavioural biases in mutual fund investing

1. Why should mutual fund investors care about behavioural biases?

Because over time, behaviour often matters more than fund selection. Research finds biases like loss aversion, herd mentality and overconfidence significantly reduce realised returns for many investors, even when they choose decent funds. Fixing behaviour can add more value than endlessly chasing the “best” scheme.

2. Which bias hurts Indian mutual fund investors the most?

Studies on Indian investors suggest loss aversion is the most dominant bias, with around 70 percent of investors strongly influenced by it. It leads to panic exits in downturns, SIP stoppages and reluctance to invest during corrections, all of which weaken long-term wealth creation.

3. How do SIPs help reduce behavioural mistakes?

SIPs automate investing, remove the need to time the market, and enforce rupee-cost averaging, so you buy more units when markets are down and fewer when they are up. This structure counters timing, herd and loss-aversion driven reactions, especially in volatile phases.

4. Is following popular fund rankings a form of herd behaviour?

It can be, if you pick funds only because they are at the top of recent-return lists or heavily advertised, without checking fit for your goals and risk profile. Using rankings as one input is fine, but blindly following them is another manifestation of herd mentality and recency bias.

5. How often should I review my mutual fund portfolio to avoid bias-driven decisions?

Once or twice a year is enough for most investors. Frequent checking increases the emotional impact of short-term volatility and makes loss aversion and recency bias worse. Structured, periodic reviews with clear criteria help you act calmly rather than react to every market move.

6. Can financial education really reduce these biases?

Education helps, but by itself is not enough. Studies show that higher financial knowledge does improve intention and decision quality, but emotions and social influences still matter. The best results come when awareness is combined with simple systems: SIPs, written plans, and, where needed, guidance from a SEBI-registered adviser.

7. What is one simple step to start managing my biases today?

Write down your top 3 financial goals, the time horizon for each, and a rough asset allocation for them. Then set up or adjust your SIPs to match that plan, and commit to reviewing only twice a year. This single step shifts decisions from emotion-driven reactions to goal-driven actions.