ETFs, index funds and actively managed funds: differences, costs and taxes
By the MeridIAn Screener team · Published on 13 October 2026 · 6 min read
If you don’t want to pick companies one by one, there are three ways to buy many at once: an actively managed mutual fund, an index fund or an ETF. They look alike, but they cost different amounts, you buy them differently and they’re taxed differently. Here are the differences, with numbers, so you know what to ask before choosing.
Three ways to invest in many companies at once
- Actively managed fund. A manager decides what to buy and sell, aiming to do better than the market (its benchmark index). You pay for that.
- Index fund. It doesn’t try to beat the market: it copies an index (for example, the S&P 500, with about 500 large US companies) and charges very little. As a mutual fund, you buy and sell it once a day, at the closing price (net asset value, NAV).
- ETF (exchange-traded fund). Almost always it copies an index, just like an index fund, but it trades on the stock exchange like a share: you buy it through a broker, at any time during the session and at that moment’s price.
The first US ETF was launched in 1993 and tracks the S&P 500. Today there are ETFs for almost everything: countries, sectors, bonds, commodities and specific strategies.
The differences at a glance
| Active mutual fund | Index mutual fund | ETF | |
|---|---|---|---|
| Goal | Beat its index | Copy the index | Copy the index (almost always) |
| Where you buy it | Fund company or brokerage | Fund company or brokerage | Brokerage, on the exchange |
| Price | Once a day (NAV) | Once a day (NAV) | Changes throughout the session |
| Typical annual costs (expense ratio) | Often 0.5% to 1% or more | 0.02% to 0.2% for the large ones | 0.03% to 0.5% |
| Other costs | Sometimes sales loads or 12b-1 fees | Usually none | Bid-ask spread (commissions are $0 at most brokers) |
| Minimum investment | Often $1,000 to $3,000 | Often $0 to $3,000 | One share, or less with fractional shares |
| Capital gains distributions | Common: taxable every year in a regular account | Few | Rare (ETFs can usually avoid them) |
| Automatic monthly investing | Easy | Easy | Possible at many brokers |
The cost that matters most: the annual fee
The expense ratio is charged every year on all your money, whether you win or lose, and it eats into compound interest. It looks small, but over 30 years it’s huge:
Example: you invest $10,000 for 30 years and the market returns 7% a year before costs. What you would end up with, by annual fee:
| Annual costs | Value after 30 years | What they cost you |
|---|---|---|
| 0.2% (cheap ETF or index fund) | $71,968 | $4,155 |
| 0.6% | $64,306 | $11,817 |
| 1.2% | $54,271 | $21,852 |
| 1.8% (expensive active fund) | $45,759 | $30,364 |
With no costs at all it would be $76,123. The gap between the cheapest and the most expensive is more than $26,000, on an initial investment of $10,000.
Besides the expense ratio, check any sales charge, account fees and, for ETFs, the bid-ask spread (the gap between the buy and sell price on the exchange, tiny for large ETFs). If the fund invests abroad, currency costs are already built into its returns. The broker comparison helps with the broker side.
Is active management worth paying for?
An active fund is only worth it if, after its costs, it beats the index. The data isn’t encouraging: according to S&P Dow Jones Indices’ SPIVA U.S. Year-End 2025 scorecard, 79% of active large-cap US equity funds trailed the S&P 500 in 2025 alone, and over long periods most of them fall behind too.
Some managers do beat the market for years, but it’s hard to know in advance which ones, and those who manage it in one period often don’t repeat it in the next. That’s why many investors use index funds or ETFs for the core of their portfolio and keep active management, if they use it at all, for specific parts.
How they’re taxed in the US
For a US investor the key question is which account the fund sits in:
- Tax-advantaged accounts (401(k), traditional IRA, Roth IRA, HSA): what happens inside isn’t taxed each year. You pay when you withdraw (traditional) or not at all if you follow the rules (Roth). Here the differences between funds and ETFs barely matter.
- Regular (taxable) brokerage account: you pay tax every year on dividends and on any capital gains the fund distributes, even if you reinvest them. Active mutual funds often distribute gains when the manager sells; index funds, few; ETFs, rarely, because of the way shares are created and redeemed. That makes ETFs and index funds more tax-efficient.
- When you sell: the gain is short-term (held a year or less, taxed like wages) or long-term (0%, 15% or 20%). Qualified dividends get the long-term rates. You can estimate it with our capital gains tax calculator.
- Losses and the wash sale rule: if you sell at a loss and buy the same or a substantially identical fund within 30 days before or after, you can’t deduct the loss that year. Switching to a fund that tracks a different index avoids it.
General summary as of October 2026. Taxes change and every case is different: check IRS.gov or a tax professional.
What to check in an ETF or index fund
| Item | What it is | Why it matters |
|---|---|---|
| Index | What it copies (S&P 500, total US market, MSCI World ex-US…) | It’s your real investment: how many companies, which countries, which sectors |
| Expense ratio | Annual fee | The cost that matters most in the long run |
| Assets | Money under management | Very small funds are more likely to close |
| Tracking difference | How far it lags the index each year | Measures the real cost, beyond the expense ratio |
| Bid-ask spread and volume | How easily it trades | Large ETFs trade with tiny spreads; niche ones can cost more |
| Distributions | Dividends and capital gains it pays out | In a taxable account they’re taxed each year |
| Domicile | Where the fund is based | Stick to US-domiciled funds: foreign funds are usually PFICs, with harsh tax rules for US investors |
Which one fits each case?
| If… | Usually fits better |
|---|---|
| You invest a little every month for many years | A low-cost index fund or ETF with automatic investing |
| You want to buy and sell during the session, or a very specific market | ETF |
| Your 401(k) only offers a few funds | Usually the lowest-cost index fund on the menu |
| You believe in a specific manager and accept paying more | Active fund, knowing most don’t beat their index over time |
If you’d rather pick individual companies, a screener helps you filter them: see what a stock screener is.
- Active funds, index funds and ETFs let you buy many companies at once; the last two copy an index at a very low cost.
- Over 30 years, going from a 0.2% to a 1.8% annual fee can cost more than you invested.
- In a regular account, ETFs and index funds are usually the most tax-efficient; in a 401(k) or IRA the difference barely matters.
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General information for educational purposes. Not financial or tax advice, nor a recommendation to buy or sell securities. Investing in shares involves the risk of loss. · Contact: info@meridianscreener.com