What Is an
Index Fund?

An index fund is a pool of money from many investors that buys all the stocks in a specific market index — like the S&P 500 (largest 500 US companies), the FTSE 100 (largest 100 UK companies), the ASX 200 (largest 200 Australian companies), or the TSX 60 (largest 60 Canadian companies). Instead of paying a fund manager to pick winners, the fund just copies the index, holds the same stocks in the same proportions, and charges a tiny fee for doing so. You get the average return of the index (minus the fee), which historically has beaten 90%+ of actively managed funds over 20-year periods.

Two ways. (1) Price appreciation — the stocks inside the fund go up over time, so your share of the fund goes up too. (2) Dividends — the companies inside the fund pay dividends to shareholders, which the fund either pays out to you in cash or automatically reinvests. The S&P 500 has averaged about 10% total annual return (price + dividends) over the last 30 years, with significant variation year to year (the worst calendar year in that window was 2008 at -37%; the best was 2013 at +32%). Long-term, the compounding is what matters.

An index fund is the strategy — passively tracking an index. An ETF (exchange-traded fund) is one of two wrappers that strategy can come in; the other is a traditional mutual fund. ETFs trade on a stock exchange like individual stocks (you buy/sell at intraday prices), are usually slightly more tax-efficient in taxable accounts (especially in the US), and tend to have slightly lower expense ratios. Mutual fund index funds settle once a day at the end-of-day NAV (net asset value), but offer fractional-share purchases and automatic-contribution programs that ETFs sometimes don't. Vanguard VTSAX (mutual fund) and VTI (ETF) hold essentially the same underlying portfolio — total US market — with marginally different mechanics.

The expense ratio is the annual fee the fund charges, expressed as a percentage of your invested balance. A 0.03% expense ratio means $3 per year on a $10,000 balance. The cheapest index funds today charge 0.03-0.10% per year (Vanguard VTI, Fidelity FZROX, iShares ITOT, Schwab SWTSX in the US; Vanguard VAS or Betashares A200 in Australia; Vanguard VFV or XEQT in Canada). Actively managed funds typically charge 0.50-1.50% per year. Over 30 years, the difference between a 0.03% index fund and a 1% active fund can cost you 25-30% of your final balance to fees alone. This is the single biggest reason index funds beat active funds over long periods.

Index funds are not risk-free — they own stocks, and stocks fluctuate. In 2008 the S&P 500 dropped 37%; in March 2020 it dropped 34% in five weeks. But they are diversified — owning the entire market means no single company can ruin you. The risks are market-wide drawdowns (which historically recover within a few years) and inflation (which erodes purchasing power even when your nominal balance grows). The standard advice — invest only money you don't need for 5-10 years, diversify globally, and don't sell during drawdowns — applies in full to index funds. They are NOT insured by the FDIC / FSCS / equivalent because they aren't bank deposits.

The orthodox answer for most working-age investors: as much of your long-term savings as you can afford after covering an emergency fund and high-interest debt. The Bogleheads three-fund portfolio (US total stock + international stock + total bond) is a common starting point. Asset allocation depends on age, risk tolerance, and tax-advantaged-account limits (401(k), Roth IRA, HSA in the US; super in Australia; RRSP and TFSA in Canada; ISA and SIPP in the UK). Use Richify's compound interest calculator to project what regular monthly contributions to an index fund grow to over 10/20/30 years at the historical S&P 500 average return.

This is personal but the most common picks: For US investors — Vanguard VTI (total US market, 0.03% ER) or VOO (S&P 500, 0.03% ER) for stocks; VXUS (total international ex-US, 0.07% ER) for diversification. For Australian investors — Vanguard VAS (ASX 300, 0.07% ER), Vanguard VGS (developed-markets ex-Australia, 0.18%), or Vanguard VDHG (all-in-one diversified, 0.27%). For Canadian investors — Vanguard VFV (S&P 500 in CAD, 0.09%) or XEQT (all-equity ETF, 0.20%). For UK investors — Vanguard VWRL (FTSE all-world, 0.22%) or HSBC HMWO. Richify doesn't sell or recommend specific funds — these are widely-cited examples by independent finance writers. Check the expense ratio, the index tracked, and the tax-efficiency in your account type before buying.

Three structural reasons backed by SPIVA (S&P Indices vs Active) data and Morningstar's Active/Passive Barometer. (1) Fees compound — an active fund charging 1% per year has to outperform the index by 1% per year just to break even with you, which is mathematically a high bar. (2) Survivorship bias — the active funds that underperform get shut down, so the average performance of surviving active funds looks better than reality. (3) The market is dominated by professional traders — when one beats the index, another must lose to them; collectively, active managers ARE the market (minus fees). Over 20 years, ~85-95% of active US large-cap funds underperform the S&P 500 net of fees, depending on the SPIVA report year.