Every investor knows they should buy low and sell high. In a crash almost nobody does, and the ones who fail are not stupid — they are running perfectly normal human software on a problem it was not built for.
Understanding the specific failure modes is the only defence that works, because the one thing you cannot do in the moment is reason your way out.
Why a fall feels worse than a rise feels good
Loss aversion is the foundational finding: a loss registers roughly twice as strongly as an equivalent gain. A portfolio down 20% does not feel like the mirror image of one up 20%. It feels about twice as urgent.
That asymmetry is why “just hold on” is such weak advice. It asks you to override a response that is doing exactly what it evolved to do.
Layered on top:
- Recency bias. Whatever is happening now feels permanent. In March 2020 the fall felt endless; by late 2021 the rise did.
- Herding. Everyone selling is powerful evidence that selling is correct — and it is the single least reliable signal available, because it peaks at the bottom.
- Availability. Vivid, repeated headlines make catastrophe feel probable. The coverage is loudest precisely when the risk has already been priced in.
- Action bias. Doing nothing feels negligent. In investing it is usually the highest-value action available, and it is the hardest to take.
The two mistakes that do the damage
Mistake one: selling into the fall. This converts a temporary decline into a permanent loss. The units are gone and do not participate in the recovery.
Mistake two, which is worse: not coming back. Having sold, the investor waits for “clarity”. Clarity arrives well after the recovery, so they re-enter higher than they left. This is buying high and selling low with extra steps, and it is the largest documented source of the gap between what funds return and what investors actually earn.
There is a third, quieter one: stopping the SIP. A SIP’s entire mathematical benefit comes from buying more units when prices are low. Pausing during a fall means the mechanism is switched off in the only period it was going to help — see rupee-cost averaging.
The defences that actually hold
Willpower is not one of them. What works is deciding in advance, while calm:
- An allocation you can survive. If a 40% equity fall would force or panic you into selling, your equity share is too high — regardless of what a risk questionnaire said. This is the real job of asset allocation.
- An emergency fund that is not equity. Most forced selling is not sentiment; it is a job loss meeting a portfolio. Six months of expenses in a liquid or short-duration fund removes the mechanism.
- Automation. A SIP that continues by default requires an active decision to stop. Make the good behaviour the path of least resistance.
- A written investment policy. One page, written in a calm month: what you own, why, and what would legitimately make you sell — the genuine reasons, not “it fell”. Read it during a crash instead of the news.
- Rebalancing as a rule, not a judgement. Pre-committed bands force you to buy the asset that fell without anyone having to feel brave about it.
- Look less. Loss aversion is triggered by observation. Checking a portfolio daily during a fall guarantees you experience every decline and none of the long-run compounding.
Pitfalls to avoid
- Do not confuse “I have a high risk appetite” with capacity. Appetite is measured on a form in a bull market; capacity is measured by cash flows and horizon.
- Do not wait for the bottom to re-enter. It is only identifiable afterwards. If you must move, move on a schedule rather than a view.
- Do not treat a crash as evidence your fund is bad. Everything in the category fell. Compare against the peer group, not against zero.
- Do not go looking for confirmation. In a fall, every forecast you seek out will agree with your fear, because that is what gets published.
Key takeaway
A crash is not primarily a test of analysis; it is a test of pre-commitment. Every decision that protects you must be made before the fall, because during it your judgement is measurably impaired and you will not notice. Set an allocation you can hold through a 40% decline, keep a non-equity emergency buffer, automate the contributions, write down what would genuinely justify selling — and then, when it happens, do considerably less than feels right.
Terms used here
More in Module 5 — Advanced metrics, taxation and wealth architecting
Mutual fund taxation decoded: short-term vs long-term capital gains
Equity, debt, hybrid and ELSS are taxed under different rules, and the rules changed twice in three years. What applies now, and to which of your units.
Decoding alpha and beta: manager skill versus market risk
Beta is how much market you took; alpha is what you got beyond it; R² tells you whether either number means anything. Read in that order, they catch a closet index fund.
Absolute, CAGR, XIRR: which return are you looking at?
Three numbers that all answer “how did it do?” and disagree with each other. Which one your statement shows, which one this site shows, and when each is the honest one.
Rolling returns, and the start date that flatters a fund
A trailing return runs from one day to one day, and moving either changes it. What sliding that window across the whole history shows that a single figure cannot.
Sharpe and Sortino: measuring risk-adjusted returns
Volatility, Sharpe, Sortino and maximum drawdown measure four different things, and only one of them predicts whether you will still be holding in year three.
Treynor and information ratio: advanced tools for comparing funds
One prices market risk, the other prices the decision to differ from the index. For choosing between active funds in one category, the information ratio is the most relevant number on the page.
Tracking error and standard deviation in passive funds
One measures how much a fund moves, the other how much it moves differently from its index — and neither is the number that actually reaches your returns.
What is portfolio turnover ratio? Decoding a fund’s trading activity
How much trading it took to produce the returns, the invisible costs that come with it, and why the number is a consistency check rather than a verdict.
Credit risk and yield-to-maturity in debt funds
A high YTM is a description of the risk taken, not a forecast of the return earned. How to read it beside the rating profile, and what a credit event permanently does.
Factor investing and smart beta: beyond market-cap weighting
A disclosed, rules-based tilt at a fraction of active cost — and active risk by another name, with long stretches of underperformance that are the reason the premium exists.
Estate planning for mutual fund investors: transmission and legalities
Nomination, a will and joint holding — what each one actually does, what transmission involves without them, and why inheriting does not reset the capital-gains clock.