How to start understanding investments

In a nutshell

Investing means keeping money somewhere it can earn something over time. Before you invest, pay off expensive debt and build an emergency fund. Then compare three things: risk, time frame and how easily you can take the money out. No serious investment guarantees high returns.

Before you invest

Expensive debt eats more money than a regular investment gives back. Credit card revolving balances, overdrafts and personal loans usually charge monthly interest far above what a simple investment earns. So the usual order is: pay off expensive debt, then save an emergency fund, and only then think about longer goals.

Example

Ana has R$ 1,000 to spare. She also owes R$ 1,000 on her credit card. Suppose, just as an example, that the debt charges 10% a month and an investment earns 0.8% a month.

• Debt interest in one month: R$ 1,000 × 10% = R$ 100.
• Investment earnings in one month: R$ 1,000 × 0.8% = R$ 8.
• If Ana invests and keeps the debt, she earns R$ 8 and loses R$ 100. She ends the month R$ 92 poorer.

After paying off the card, Ana starts saving R$ 1,000. With the same hypothetical 0.8% a month, after 12 months, with earnings adding up on top of earnings, she would have about R$ 1,100.34. These are example numbers: real returns change and may be higher or lower.

Risk, time frame and liquidity

• Risk: the chance that the value drops or that you don't get what was promised.
• Time frame: how long the money needs to stay invested.
• Liquidity: how fast you can turn the investment back into cash in your account. Daily liquidity means you can withdraw on any business day.

Emergency money needs low risk and high liquidity. Money for many years from now can accept a longer time frame.

Fixed income and variable income

In fixed income, the earning rule is set when you invest. It can be a fixed rate or tied to an index, such as the Selic, Brazil's basic interest rate. In variable income, such as stocks, the value goes up and down every day, and nobody knows the result in advance.

• Poupança (Brazilian savings account): simple and easy to withdraw. Under the current Brazilian rule, when the Selic is above 8.5% a year, it earns 0.5% a month plus the TR, a reference rate. With the Selic at 8.5% or less, it earns 70% of the Selic plus the TR. Earnings are paid once a month, on the deposit's monthly "anniversary".
• Tesouro Selic: a Brazilian government bond that follows the Selic rate. It is backed by the National Treasury, not by the FGC. If you sell before maturity, you get that day's value.
• CDB: you lend money to a bank, and the bank pays interest. It is covered by the FGC, Brazil's deposit guarantee fund. Today, the FGC covers up to R$ 250,000 per CPF (Brazilian taxpayer ID) at each institution or financial group, adding up everything you hold there (poupança, CDBs and others), with an overall cap of R$ 1 million every 4 years. Check the rules on the FGC website.

Taxes: under Brazilian rules in force in 2026, poupança pays no income tax for individuals. CDBs and Tesouro Direto pay income tax on the gain, from 22.5% down to 15%: the longer the money stays invested, the lower the rate. If you withdraw within 30 days, IOF (a tax on financial transactions) also applies. Tax rules can change by law, so check before investing.

Step by step

1. List your debts and the interest on each. Start by paying off the most expensive one.
2. Decide how much you want in your emergency fund.
3. For each goal, write down the time frame: months or years away.
4. Before investing, ask: what is the risk, what is the time frame, and when can I withdraw?
5. Compare returns after fees and taxes, when there are any.
6. In Meu Gasto, open Net worth and record your investments at today's value. Update them once a month to see how they change.

Common mistakes

• Investing while carrying expensive debt. Pay off the debt first: its interest is usually higher than the return.
• Believing in guaranteed high returns. A promise of big, risk-free gains is a sign of a scam. Be suspicious and don't send money.
• Keeping your emergency fund in something that swings a lot. That money must be available and stable when you need it.
• Choosing only by return. Also look at the guarantee, the time frame and liquidity.
• Following tips from strangers. Understand the product first. Meu Gasto doesn't recommend investments: it helps you keep track of what you already have.