Understanding CDB: How It Works and Its Benefits
Have you heard of CDB and felt it’s something complicated, reserved for finance experts? The good news is that the Certificate of Bank Deposit — that’s its full name — is one of the simplest and most accessible fixed-income investments in the Brazilian market. Large banks, mid-sized banks, and fintechs offer this option, and today you can start investing with very low amounts, directly from your mobile phone.
In this article, we will explain what a CDB is, how it works in practice, its advantages, the risks you need to be aware of, and how taxation works. Our goal is that, by the end of your reading, you can make more informed decisions — not just about CDBs, but about any fixed-income product that comes your way.
Before investing in any product, remember: building a solid financial foundation is the first step. This includes having an organized budget. If you wish, check out our guide Personal Budget: How to Set Up Yours Step by Step before taking the next leap.
What Exactly is a CDB?
The CDB (Certificate of Bank Deposit) is a fixed-income security issued by financial institutions — banks, finance companies, and credit societies. When you buy a CDB, you are essentially lending money to the bank. In return, the institution agrees to return this amount on the agreed date, with interest.
This mechanism is simple and has existed for decades in Brazil. Banks use the funds raised via CDB to finance their credit operations — loans, financing, personal credit. As an investor, you receive compensation for this.
It’s important to clarify: CDB is a fixed-income product, meaning the form of remuneration is defined at the time of application. However, this does not mean the final value is entirely predictable in all cases — especially in post-fixed CDBs, as we will see later.
How CDB Compensates the Investor
There are three main types of remuneration in CDB:
Post-Fixed CDB
This is the most common type. The profitability is linked to an index, almost always the CDI (Interbank Deposit Certificate), which closely follows the Selic rate, set by the Central Bank’s Monetary Policy Committee (Copom).
The post-fixed CDB is usually offered as a percentage of the CDI — for example, 100% of the CDI, 110% of the CDI, or 90% of the CDI. The higher the percentage offered, the greater the potential return. However, the exact amount you will receive is only known at the end, as it depends on how the CDI varied over the period.
> How to check the current CDI: visit the Central Bank of Brazil’s website (bcb.gov.br) or B3’s website (b3.com.br), which publishes the DI rate daily.
Pre-Fixed CDB
In this case, the interest rate is set at the time of contracting — for example, 12% per year. You already know exactly how much you will receive at the end of the term, if you keep the investment until maturity. The downside is that if the Selic rate rises significantly, your pre-fixed CDB may yield less than other options available in the future.
Hybrid CDB (IPCA+)
Less common but existent: the return combines a fixed percentage with the variation of the IPCA (Broad Consumer Price Index), Brazil’s official inflation index. It works similarly to the IPCA+ Treasury, but issued by a bank. It protects the investor’s purchasing power against inflation.
Liquidity: When You Can Withdraw Your Money
This is a critical point that many beginner investors overlook. In CDB, liquidity varies significantly from product to product:
- Daily liquidity CDB: allows withdrawal at any time, even before maturity. It is useful for emergency funds or short-term goals.
- CDB without early liquidity: the money is locked until the maturity date. Withdrawing early may be impossible or cause losses, depending on the institution’s conditions.
- CDB with a grace period: there is a minimum period before you can withdraw.
Practical rule: always check the liquidity policy before applying. Never place money you might need before maturity in a CDB without daily liquidity.
Taxation: What You Pay to the Government
CDB is taxed by the Income Tax (IR), which applies to earnings (not on the principal amount). The rate follows the regressive IR table for fixed income, defined by the Federal Revenue:
| Application Term | IR Rate |
|---|---|
| Up to 180 days | 22.5% |
| From 181 to 360 days | 20% |
| From 361 to 720 days | 17.5% |
| Above 720 days | 15% |
The longer you keep the investment, the lower the rate — and the higher the net return. The IR is withheld at source at the time of redemption, meaning you receive the net amount.
There is also the IOF (Tax on Financial Operations), which applies only to redemptions made within 30 days of the application, with a decreasing rate from the first to the thirtieth day. After 30 days, IOF is not charged.
> Important: the rules and rates above are current according to federal legislation. Always confirm with the Federal Revenue (gov.br/receitafederal) if there have been changes.
FGC Protection: What It Is and What the Limits Are
One of the most cited advantages of CDB is the coverage by the FGC (Credit Guarantee Fund). The FGC is a non-profit private entity that protects depositors in case of bankruptcy or intervention in an associated financial institution.
The current coverage limits are:
- R$ 250,000 per CPF per financial institution, per financial conglomerate.
- Global cap of R$ 1,000,000 per CPF, renewable every 4 years in case of activation.
This means that if you have R$ 300,000 in CDBs from a single bank and it goes bankrupt, the excess R$ 50,000 will not be covered.
> How to check: visit the official FGC website (fgc.org.br) to check updated limits and which institutions are associated.
The FGC provides an important layer of security but does not eliminate all risks. Diversifying among different institutions is a prudent strategy for those with amounts above the coverage limit.
Advantages and Disadvantages of CDB
Every investment has two sides. Here’s a balanced comparison:
| Criterion | Advantage | Disadvantage / Risk |
|---|---|---|
| Accessibility | Available in banks and apps with low initial value | Conditions vary greatly between institutions |
| Security | FGC coverage up to R$ 250,000 per institution | Credit risk of the issuing institution |
| Profitability | Can surpass savings and similar products | Depends on CDI percentage and term |
| Liquidity | Options with daily liquidity available | Higher-yield CDBs generally have a fixed term |
| Taxation | Rate decreases over time (regressive table) | IR reduces gross yield; no exemption as in some competitors |
| Predictability | Clear remuneration rules from the start | Post-fixed depend on CDI variation |
How to Invest in CDB Practically
If you already have an organized budget and an emergency fund, and want to take your first steps with CDB, here’s how the general process works:
- Define your goal and term: is the money for an emergency fund (use CDB with daily liquidity), for a medium-term goal (1 to 3 years), or long-term (over 2 years)?
- Choose a financial institution: traditional banks, digital banks, and brokers offer CDBs. Compare available offers — CDI percentage, term, and liquidity.
- Check if the institution is associated with the FGC: consult the FGC website.
- Evaluate the minimum amount: some options require low amounts (sometimes R$ 1.00), others have higher minimums in exchange for more attractive rates.
- Read the conditions before applying: maturity term, early redemption policy, and taxation.
- Apply and monitor: periodically monitor the yield and if the conditions still make sense for your goals.
Conclusion: Is CDB Right for You?
CDB is an accessible, regulated fixed-income product with a relatively simple structure to understand. For those starting to invest or looking for alternatives to savings, it can be an interesting path to explore — especially when comparing rates, terms, and FGC coverage among different institutions.
However, “interesting to explore” does not mean “right for everyone.” Your risk profile, goals, term, and liquidity needs are factors that need to be individually analyzed. A long-term CDB with restricted liquidity may be great for someone with well-defined goals and an already formed emergency fund, but terrible for someone who might need the money at any moment.
The most important thing is to make informed decisions. And this starts long before choosing a financial product: it starts with a well-structured budget. If you don’t have yours yet, the guide Personal Budget: How to Set Up Yours Step by Step can be an excellent starting point.
> Important Note: This article is for educational and informational purposes only. It does not constitute investment advice, financial consultancy, or a suggestion to purchase any specific product. Data, rates, and rules presented reflect the knowledge available at the time of publication and may change — always consult official sources (Central Bank, Federal Revenue, FGC, B3, CVM) to confirm updated information. For investment decisions suitable to your profile and financial situation, consult a professional duly registered with the CVM (Securities and Exchange Commission).
