Common Investor Mistakes
When everything is rising and news is positive, you feel the urge to jump in. Buying after euphoria can increase the risk of entering with little margin of safety.
Consequence
You may enter at demanding prices. A 10-15% correction is normal and may take months to recover, causing anxiety.
How it is usually handled
Many investors spread their entry over regular contributions (DCA) so as not to depend on a single price. A model's signal does not take your horizon, liquidity or risk tolerance into account.
Are you doing this?
Have you bought impulsively after reading positive news?
The market drops 20% and you sell everything to "protect" what's left. Impulsive selling can lock in losses before checking whether the plan still makes sense.
Consequence
You may crystallize losses and miss a later recovery, which is never guaranteed and has no fixed timeline.
How it is usually handled
It is common to write down, before investing, how big a fall you are willing to sit through. If a 25% drop would make you sell, that equity exposure probably does not fit that profile.
Are you doing this?
Do you have a written plan for what you'll do if the market drops 30%?
Waiting for the market to "bottom out" to buy or to "be about to fall" to sell. Nobody achieves this consistently.
Consequence
You miss the best market days. Missing the 10 best days in 20 years cuts your returns in half.
How it is usually handled
Many investors contribute at fixed intervals (DCA) precisely so they do not have to pick the moment. No model, including this site's, has shown it can time the market reliably.
Are you doing this?
Have you ever waited weeks to buy because "it was going to drop more"?
A 1.5% TER vs 0.20% seems small, but over 20 years it can cost tens of thousands of euros.
Consequence
With €100,000 and a 7% gross annual return, a 1.5% TER leaves about €137,000 less than a 0.20% TER after 25 years.
How it is usually handled
Before buying, people usually compare ongoing charges (TER), purchase and custody fees and tax treatment; the annual cost statement shows what was paid. The fee calculator shows the long-term effect.
Are you doing this?
Do you know exactly how much you pay in fees each year?
"Tesla will go up", "tech always rises", "my company gives me free shares". Concentration multiplies risk.
Consequence
If your concentrated position drops 50% (normal for individual stocks), you need 100% gain just to recover.
How it is usually handled
A global ETF spreads risk across hundreds or thousands of companies in several regions; each ETF page shows which index it tracks and how many holdings it has.
Are you doing this?
Is more than 20% of your portfolio in a single asset?
Investing all savings without a safety cushion. When an unexpected expense arises, you're forced to sell investments — probably at a loss.
Consequence
Forced sales at the worst time + tax impact. The market doesn't respect your bills.
How it is usually handled
The usual practice is to keep a buffer of 3-6 months of expenses before investing and not to invest money that may be needed within five years.
Are you doing this?
If you lose your job tomorrow, can you live 4 months without touching your portfolio?
Checking your portfolio daily doesn't make you a better investor. On the contrary: it exposes you to noise and increases the probability of emotional decisions.
Consequence
The S&P500 is up 53% of days but 95% of 20-year periods. If you check daily, you'll see red almost half the time.
How it is usually handled
Many investors check their portfolio at a fixed frequency, monthly or quarterly, to cut out noise. The weekly newsletter sums up the context without opening the broker.
Are you doing this?
Do you open your broker app more than 3 times a week?
"This influencer made 200%". Content creators show their wins, never their losses. Survivorship bias is brutal.
Consequence
You can end up buying complex or volatile products you don't understand, with a high risk of loss.
How it is usually handled
Asking for verifiable data, methodology, costs and risks helps separate real results from anecdotes. This site's walk-forward backtest is educational material, not a promise of returns.
Are you doing this?
Can you explain in one sentence why you bought your last position?
If your target allocation is 70/30 (equity/bond) and you don't rebalance, after a rally you could end up at 90/10 — much more risk than intended.
Consequence
Your actual risk profile drifts from your target. In the next correction, the impact can be disproportionate.
How it is usually handled
Rebalancing means bringing the portfolio back to its target weights, on a schedule or when it drifts beyond a threshold. The model portfolio is educational: it shows how a composition changes, not what weights yours should have.
Are you doing this?
Does your actual portfolio resemble the exposure you intended to take?
Buying a financial product because "someone recommended it" without understanding its contents, behavior, or risks.
Consequence
When it drops, you don't know if it's normal or if you've actually lost money. Uncertainty generates panic.
How it is usually handled
The Academy explains what an ETF is, what it costs and what risks it carries; each ETF page details what it holds and which index it follows.
Are you doing this?
Can you explain the 12 ETFs in your portfolio to a friend in 2 minutes?
Methodology
Common investing mistakes and practical examples
Study concentration, performance chasing, hidden costs and emotional decisions. Each example connects a common mistake with a question to ask before acting.
Several funds can hold the same companies: counting ETFs is not a measure of diversification. Compare underlying exposures, costs and your time horizon rather than only the latest return.
LearnAImarkets · Methodology
Methodology: Educational content with illustrative assumptions. Calculators do not forecast returns. Change the inputs to explore different scenarios. Methodology
Educational information, not investment advice. Investing involves risk of loss.