Feeling Too Exposed in Your Index Fund? A Top-10 Weight Check Instead of a Prediction

• Step 1: Look up the top-10 weight
• Step 2: Work out your real exposure
• Step 3: Stress-test the mix, not the forecast
• Step 4: Adjust without selling
• Keep a cash buffer separate
• Free tools

A broad index fund is diversified across hundreds of companies, but it is weighted by company size. When a few giant companies grow, they become a large share of the fund. If that worries you, you do not need to predict a crash. You can measure your exposure and decide on a mix you can hold.

§Step 1: Look up the top-10 weight

The fund’s fact sheet lists its top 10 holdings and their combined weight. A large-cap US index can have a third or more in its top 10. A total world index usually has less.

§Step 2: Work out your real exposure

Example portfolio: $40,000 in a US large-cap index fund + $10,000 in a bond fund = $50,000.
If the top 10 are 35% of the stock fund: $40,000 × 0.35 = $14,000, which is 28% of the whole portfolio.

§Step 3: Stress-test the mix, not the forecast

Ask: if stocks fell 35%, could I hold?

• $40,000 stocks × 0.35 drop = −$14,000
• Portfolio goes from $50,000 to about $36,000 (bonds roughly flat in this example)

If that number would make you sell, the stock share is probably too high for you. That decision is about you, not about the market.

§Step 4: Adjust without selling

• Point new contributions at the part you’re underweight (bonds, an equal-weight fund, small caps, or international) until the mix matches your target.
• Rebalance once a year back to your target percentages.
• Inside tax-advantaged accounts (401k, IRA, ISA), switching funds usually has no tax cost. In a taxable account, selling can trigger capital gains, which is why redirecting new money is often the cheaper fix.

§Keep a cash buffer separate

Money you may need in the next 1-3 years (emergency fund, a home deposit) usually belongs outside stocks entirely, so a drop never forces a sale.

§Free tools

• Investment calculator: https://smartbudgetsheets.surge.sh/calculators/investment-calculator/?utm_source=nostr
• Compound interest calculator: https://smartbudgetsheets.surge.sh/calculators/compound-interest-calculator/?utm_source=nostr
• Emergency fund calculator: https://smartbudgetsheets.surge.sh/calculators/emergency-fund-calculator/?utm_source=nostr
• Debt Payoff Planner, up to 8 debts (Payhip): https://payhip.com/b/PtBLU?utm_source=nostr
• 42 free budget templates, pay what you want ($0 is fine): https://smartbudgetsheet.gumroad.com/l/ngpkrb?utm_source=nostr

General information, not financial advice. Figures are rounded examples.