The mistakes almost every new investor makes

Mistakes made before the first investment

These cost the most and are the least discussed, because they happen before anyone thinks of themselves as an investor.

• Investing with no emergency fund. The most expensive mistake in this lesson. Without cash reserves, an ordinary emergency forces you to sell during a fall, which turns a temporary drop into a permanent loss. Three to six months of expenses first, always.
• Investing while carrying a credit card balance. At 36% to 42% a year, clearing that debt is a guaranteed return no investment can match. Investing instead is a choice to earn perhaps 12% while paying 40%.
• Investing money needed within three years. Equity over short periods can do anything. This is not a risk you took, it is a mistake in matching.
• Buying an insurance policy as an investment. Endowment and money back policies typically deliver poor returns and poor cover simultaneously. Term insurance for protection, investments for growth, kept separate.
• Waiting for the right moment. Time in the market has historically mattered far more than timing it, and the perfect entry never arrives while you are waiting for it.

Mistakes when buying

• Buying on a tip. A name and a target with no reasoning cannot be evaluated and cannot be learned from. When it falls, you have no basis for any decision, because you never had a reason a fall could contradict.
• Not writing down why. Six months later the price has moved and you feel something. Without a written reason, you cannot tell whether the business changed or only the price did.
• Chasing last year winner. The best performing fund or sector of the last year is a poor predictor of the next. Buying it means buying after the rise, which is the opposite of what you intend.
• Confusing a cheap price with a cheap valuation. A ₹20 share is not cheaper than a ₹2,000 share. What matters is the price relative to what the business earns. See financial ratios.
• Buying only what you have heard of. Familiarity is not analysis. Recognising a brand tells you nothing about whether its shares are reasonably priced.
• Ignoring the expense ratio and choosing a regular plan unknowingly. A cost difference of one percentage point compounds into a large sum over twenty years.

Mistakes while holding

• Checking every day. Three hundred opportunities a year to feel something and act on it. Daily checking converts a long term investment into a series of short term decisions, and the decisions are the problem.
• Stopping a SIP when the market falls. Falls are when a SIP buys the most units for the same money. Stopping then removes most of the reason for having one.
• Never rebalancing. After a strong equity run your allocation drifts and your risk quietly rises, right when prices are already high.
• Buying more of a falling position to average down, without reassessing. Adding to a good business at a lower price is sound. Adding to a deteriorating one is throwing money at a mistake to avoid admitting it.
• Holding too many things to follow. More than about twenty holdings and most individuals stop keeping up. Positions you no longer follow are not managed, they are just owned.
• Treating a fall as automatically a reason to act. The question is never how far it fell. It is whether the business changed.

Mistakes when selling

• Selling in a panic. The most costly single action available to an ordinary investor. It converts a paper fall into a realised loss and leaves you deciding when to return, which is the hardest decision in investing.
• Selling winners and keeping losers. Locking in gains feels prudent and admitting errors feels awful, so people gradually assemble a portfolio made mostly of their mistakes.
• Waiting to get back to the purchase price. The market does not know what you paid. Your entry price is a fact about your past.
• Selling because of a headline. News is written to be read, not to be acted on. Ask whether it changes the reason you own the thing.
• Ignoring tax when selling. Selling equity at eleven months rather than thirteen changes the rate from 12.5% to 20%, and forfeits use of the ₹1.25 lakh annual exemption on long term gains.
• Never selling anything, ever. Patience is a strategy. Refusing to sell a business whose reasons have collapsed is not patience, it is attachment.

The mistakes that end accounts

Everything above costs money. These can remove the ability to keep investing at all, and each one is well evidenced.

• Investing borrowed money. It removes the one advantage an individual has, which is the ability to wait. Being right eventually is worth nothing if you are forced to close first.
• Position sizes with no cap. Putting a large share of savings into one conviction. The holding you feel most certain about is exactly where the rule should apply hardest.
• Derivatives without understanding them. SEBI found 91% of individual traders lost money in equity derivatives in FY25, with net losses of about ₹1.06 lakh crore. Over FY22 to FY24, 93% lost money and only about 1% earned more than ₹1 lakh after costs.
• Believing anyone who guarantees returns. A guaranteed high return in a market product is either a misunderstanding or a fraud. There is no third case.
• Intraday trading to recover losses. Between 65% and 71% of individual intraday traders lost money each year from FY20 to FY24. Trading to make back a loss is the most reliable way to enlarge it.

The mistake underneath the others

Nearly every error above shares one root: acting because you feel you should be doing something.

Investing is unusual in that inactivity is often the correct move, and it never feels like one. Buying because you have cash and it feels wasteful to hold it. Selling because a fall feels like it demands a response. Switching funds because a year of underperformance feels like evidence. Adding a holding because your portfolio looks too simple.

A useful test before any transaction: what specifically changed? Not what you feel, not what the price did, but what fact is different from when you last decided. If nothing changed, the honest action is usually none.

This is why the written reason matters so much. It is the only thing that lets you answer that question truthfully rather than from memory, and memory quietly rewrites itself to match how you feel today.