Common Mistakes · June 2026

Common Investing Mistakes

Long-term investing has different failure modes than active trading. These are the mistakes that consistently underperform the market index.

1. Trying to time the market

Selling before crashes, buying after recoveries. The studies are clear: most market timers underperform buy-and-hold. Fix: dollar-cost average into broad indexes.

2. Stock picking without research

Buying individual stocks based on stories. Massive underperformance vs index. Fix: default to broad-market ETFs (VTI, VOO, QQQ). Add stock picks only as smaller % of portfolio.

3. Selling in panic

Crash hits, account is down 30%, you sell at the bottom. Locks in losses. Fix: pre-commit to not selling in crashes. Automate contributions through them if possible.

4. Concentrating in employer stock

Working at and owning concentrated stock in one company = double risk. Fix: cap employer stock at 5-10% of portfolio. Diversify the rest.

5. Ignoring fees

1% annual fee compounds to ~30% of final value over 30 years. Massive drag. Fix: use index funds with sub-0.1% expense ratios (VTI, VOO, FZROX).

6. Tax inefficient placement

Holding bonds in taxable account and stocks in IRA = worst tax outcome. Fix: tax-inefficient assets (REITs, bonds, dividend stocks) in tax-advantaged accounts. Index funds in taxable.

7. Not rebalancing

After years of bull market, tech is 70% of portfolio. Concentrated risk. Fix: rebalance annually or when allocations drift > 5%.

8. Lump-sum vs DCA mistakes

Sitting on cash trying to time entry. Statistical research: lump-sum beats DCA most of the time. Fix: if you have cash, deploy it. Don't wait.

9. Overpaying for active management

Most active funds underperform passive indexes after fees. Fix: default to passive. Active only with documented edge.

10. Ignoring international/bonds

100% US stocks looks great until the decade it doesn't. Fix: include international (20-40%) and bonds (per age) for true diversification.

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