ETFs & indices

ETF or Mutual Fund: The Difference in Practice

Astron Team · 09/24/2026 · 6 min read

If you've ever researched where to invest and run into a sea of acronyms, you've probably noticed ETFs and traditional mutual funds showing up side by side in comparisons. Both do, fundamentally, the same thing: they pool money from several investors to buy a basket of assets, like stocks, bonds, or commodities.

The relevant difference isn't in what they buy, but in how you buy a share of them, how much that costs, and how it affects your taxes over time.

The core difference: when the price is set

An ETF (exchange-traded fund) is bought and sold during the trading session, at any moment the market is open, at the price prevailing at that instant. A traditional mutual fund, on the other hand, usually trades once a day, with the price calculated after the market closes, based on the total value of the portfolio's assets divided by the number of shares.

A simple way to picture this: the ETF works like a taxi, which you hail and get off whenever you want, paying that moment's fare. The traditional fund works like a bus with a fixed arrival time: everyone who boarded that day pays the same final fare, calculated only at the end of the route.

Liquidity and order types

Since it trades on an exchange all day, the ETF lets you use common stock market tools:

• Limit orders, setting the maximum buy price or minimum sell price.
• Stop orders, to automatically protect a position.
• Real-time price tracking throughout the day.

In the traditional fund, since the price is only set at the close, someone requesting a redemption in the morning will only know the exact amount received at the end of the day, which reduces control over the exact moment of entry and exit.

Costs: where the difference hits your wallet

Both types of fund charge a management fee, but the typical standard tends to differ quite a bit. ETFs that replicate broad indices tend to have lower expense ratios, because management is passive: the fund simply follows an index, with no manager trying to beat the market. Traditional active funds, since they depend on a manager constantly making buy and sell decisions, usually charge higher fees.

A simple example of how this weighs over time: for a R$ 100,000 investment, a difference of just 1 percentage point a year in the expense ratio represents R$ 1,000 less available to grow, every year, just in management cost. Over decades, with the effect of compound interest, that difference grows well beyond the isolated R$ 1,000 a year.

Taxation: a point that tends to surprise

Traditional funds that need to sell portfolio assets to pay other shareholders' redemptions can generate taxable capital gains for everyone still in the fund, even those who sold nothing. This happens because the internal sale of assets, to raise cash, is a taxable event for the fund as a whole.

ETFs, since they operate through a share creation-and-redemption mechanism with authorized institutions, without needing to sell portfolio assets on the open market as often, tend to generate fewer unexpected taxable events for those simply holding the position without selling.

Risks the two share

Neither an ETF nor a traditional fund eliminates market risk: if the portfolio's assets lose value, the share's value falls along with them, regardless of the chosen structure. Other common risks include:

• Tracking error: when the fund doesn't exactly follow the promised index or strategy.
• Liquidity risk: during moments of panic, it can be harder to sell at the expected price, especially for niche ETFs with low traded volume.
• Manager risk: in active funds, the result depends directly on the decisions of whoever manages the portfolio.

How to choose between the two

There's no single answer. Those who value the flexibility to enter and exit throughout the day, low cost, and simplicity tend to identify more with ETFs. Those seeking a specific active strategy, with a manager trying to beat the market, and who don't mind pricing only at the end of the day, might consider traditional funds.

Before deciding, it's worth checking the expense ratio, the index-tracking history (for ETFs) or the manager's track record (for active funds), and how each option fits your time horizon. Investing in either one involves risk of capital loss, and no fund structure, on its own, guarantees a positive return.