What is the difference between the Selic and CDI rates? Understand it simply
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Understanding the difference between the Selic and CDI rates is an essential step for anyone who wants to invest intelligently or simply understand how money circulates in Brazil.
Although these two indexes are often mentioned together, they play distinct roles in the economy and directly impact the pockets of Brazilians.
But what is the real difference between the Selic and CDI rates? Get ready for a clear, creative explanation based on concrete data.
What is the Selic rate?
The Selic rate is known as the basic interest rate of the Brazilian economy.
It is defined by the Monetary Policy Committee (Copom) of the Central Bank every 45 days, always with the aim of controlling inflation and guiding the cost of money in the country..
When we hear on the news that the Selic rate has risen or fallen, it means that the government is adjusting the pace of the economy.
Thus, whether to curb inflation or to stimulate consumption and investment.
To understand it in practical terms, the Selic rate works like a thermometer: if inflation threatens to rise too much, the Central Bank increases the Selic rate to make credit more expensive and, therefore, reduce consumption.
If the economy needs stimulus, the Selic rate is reduced to make credit cheaper and encourage investment.
Analogy: Imagine Selic as the conductor of an orchestra.
It sets the pace and all instruments (other interest rates) follow its lead.
If the conductor speeds up, everything becomes more intense; if he slows down, the atmosphere calms down.
In addition to directly influencing the interest charged on loans, financing and credit cards.
Selic also determines the return on fixed income investments, such as Tesouro Selic and savings.
What is the CDI?
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The CDI, or Interbank Deposit Certificate, is a very short-term security issued exclusively between banks.
Its main objective is to allow financial institutions to close the day's cash flow with a positive balance, as required by the Central Bank.
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In other words, if a bank ends the day with less money than it should, it borrows it from another bank, paying interest defined by the CDI rate.
Unlike Selic, CDI is not accessible to the common investor, but serves as a reference for the remuneration of various fixed income products, such as CDBs, LCIs and DI funds.
When you see an investment offering “100% of CDI”, it means that it will yield exactly the same as the CDI rate for that period.
Comparison table: Difference between Selic and CDI rates
| Feature | Selic rate | CDI (Interbank Deposit Certificate) |
|---|---|---|
| Who defines | Central Bank (Copom) | Interbank market (banks) |
| Main objective | Monetary policy, control inflation | Balancing bank cash flow |
| Influence | All interest rates in the country | Fixed income products and inter-bank transactions |
| Access | Indirect for individuals | Indirect, via investments linked to the CDI |
| Adjustment frequency | Every 45 days | Daily, according to interbank operations |
| Value in March 2025 | 14,25% per year | 14.15% per year (approximately) |
| Historical average difference | Selic tends to be a little higher | CDI usually slightly lower |
How are Selic and CDI related?
Despite being different, Selic and CDI go hand in hand.
The Selic serves as the maximum reference for the cost of money; the CDI, in turn, is the reflection of this cost in transactions between banks.
When Selic rises, CDI also rises, and vice versa.
This is because, if the Selic rate is much higher than the CDI, banks prefer to lend money to the government, which is safer.
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If the CDI is much higher than the Selic, banks may seek more profitable alternatives.
According to historical data, over the last 18 years, the Selic rate was, on average, only 0.06% higher than the CDI, and in 97% of that time, the Selic was equal to or higher than the CDI..
Does this seem like a small difference? In the long term, even small variations can have a significant impact on investments.
Practical example 1: Investment in CDB
Imagine that you invested R$10,000 in a CDB that yields R$100% of the CDI for 12 months.
If the annual CDI is 14.15%, at the end of the period, your gross income will be R$ 1,415.
Now, suppose you had invested in Tesouro Selic, which follows the Selic rate of 14.25% per year.
The gross income would be R$ 1,425.
This difference of R$ 10 may seem small, but over years and with larger values, it accumulates significantly.
Practical example 2: Bank loan
Suppose a bank needs to close its cash register for the day and has a deficit of R$ 1 million.
He borrows this amount from another bank, paying the current CDI rate.
If the CDI is at 14.15% per year, the cost of this loan will be proportional to this rate.
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This cost is indirectly passed on to the bank's customers, whether through interest on loans, financing or even in the remuneration of investments.
Relevant statistics
Over the last 18 years, investing in assets linked to the Selic rate yielded 875.96%.
While the CDI yielded 866.61%, an accumulated difference of 9.35%.
In short, this shows that even with seemingly small differences, the effect of compound interest makes all the difference in the long run.
Table: Evolution of Selic and CDI in recent years
| Year | Selic (%) | CDI (%) | Difference (%) |
|---|---|---|---|
| 2021 | 9,25 | 9,15 | 0,10 |
| 2022 | 13,75 | 13,65 | 0,10 |
| 2023 | 11,75 | 11,65 | 0,10 |
| 2024 | 13,25 | 13,15 | 0,10 |
| 2025 | 14,25 | 14,15 | 0,10 |
Approximate values for educational purposes, based on annual averages.
Impact of the Difference between Selic and CDI on Personal Financial Planning
The difference between the Selic and CDI rates goes far beyond a simple technical detail of the financial market.
In short, it can be decisive in building efficient personal financial planning.
Knowing how each of these rates influences your investments and debts allows you to make choices that are more aligned with your goals.
This way, whether it is to build up an emergency fund, invest for the future or even take out credit consciously.
For example, when building an emergency reserve, many experts recommend the Tesouro Selic.
In this sense, precisely because of its liquidity and because it follows the country's basic interest rate.
For medium-term goals, such as changing cars or taking a trip, products that yield a percentage of the CDI, such as CDBs and DI funds, may be more advantageous depending on the conditions offered by the bank.
The secret is to compare not only the rates, but also the costs, liquidity and taxation of each option.
Furthermore, the difference between Selic and CDI can directly influence the cost of loans and financing.
When the Selic rate rises, the cost of credit tends to increase, impacting installments on real estate financing, personal loans and even credit card revolving credit.
Therefore, monitoring the movement of these rates and understanding their differences is essential to avoid unpleasant surprises in your budget.
After all, good financial planning starts with understanding the factors that really impact your money.
Why does this difference matter to you?
The difference between the Selic and CDI rates may seem minimal, but it directly impacts the return on your investments and the cost of your loans.
If you invest in fixed income products, such as CDBs, LCIs or DI funds, your return will be linked to the CDI.
Applications such as Tesouro Selic follow the Selic rate.
Therefore, understanding this difference is essential to making smarter financial decisions.
Have you ever stopped to think about how much money you could be missing out on over the years by not knowing the difference between the Selic and CDI rates?
Difference between Selic and CDI rates: Frequently Asked Questions
1. Why is Selic always a little higher than CDI?
Selic is the basic rate set by the Central Bank, while CDI reflects operations between banks, which always seek to stay close to Selic to avoid distortions in the market.
Therefore, the CDI is usually slightly lower than the Selic..
2. If the CDI is not accessible to individuals, why is it so talked about?
Because most fixed income investments use the CDI as a yield reference.
In other words, you don't buy a CDI, but you invest in products that yield a percentage of that rate..
3. What rate should I consider when choosing an investment?
If the investment is in Tesouro Direto, consider the Selic rate. For CDBs, LCIs, DI funds and other banking products, observe the CDI percentage offered.
4. Can the difference between Selic and CDI increase?
In normal market situations, the difference is small and stable.
In crisis scenarios or sudden changes in monetary policy, there may be fluctuations, but the market tends to correct quickly to maintain balance..
5. How to track rates?
The Central Bank publishes the Selic rate after each Copom meeting. The CDI is published daily by financial market entities and can be found on investment websites.
Difference between Selic and CDI rates: Conclusion
The difference between the Selic and CDI rates is subtle, but fundamental for those who want to invest wisely or understand how the Brazilian economy works.
While the Selic is the conductor of the economy, dictating the pace of interest rates, the CDI is the reflection of this pace in operations between banks and, consequently, in the investments of millions of Brazilians.
By knowing these differences and their applications, you become a more informed investor and prepared to make better financial decisions.
Understanding the difference between the Selic and CDI rates is not just a matter of curiosity, but a powerful tool for multiplying your assets and protecting your money against market fluctuations.
After all, in the world of investments, knowledge is synonymous with profitability.
