CDI, what is it? It stands for Certificado de Depósito Interbancário (Interbank Deposit Certificate), the rate banks use to lend money to one another for one day. Calculated by B3 (Brazil’s stock exchange), it stands at about 13.65% a year in October 2026 and serves as the benchmark for CDBs (bank certificates of deposit), LCIs and LCAs (tax-exempt real estate and agribusiness credit notes) and fixed-income funds.
- The CDI is currently around 13.65% a year, or approximately 1.07% a month.
- It tracks the Selic (Brazil’s benchmark interest rate), which is at 13.75% a year, and sits slightly below the target.
- An investment paying 100% of the CDI earns the equivalent of the full rate, before Imposto de Renda (income tax).
- R$ 10,000 at 100% of the CDI for 12 months earns about R$ 1,365 gross and R$ 1,126 net.
- When the Selic falls, the CDI falls with it, and returns on floating-rate investments decline.
CDI: what it is and what it’s for
Every day, banks need to close their books with a positive balance. When a bank is short of cash, it borrows from another bank for one business day. These very short-term loans gave rise to the Certificado de Depósito Interbancário, the CDI.
The average rate on these transactions is called the DI rate, calculated and published daily by B3. In everyday market usage, almost everyone simply calls this rate “the CDI.”
Understanding what the CDI is matters because it is the main benchmark for private fixed income in Brazil. When you see a CDB paying “105% of the CDI,” its return is tied to this rate.
Is the CDI an investment?
No. You don’t buy the CDI directly: interbank certificates circulate only among financial institutions. For you, the CDI works as an index — in other words, a yardstick that determines how much an investment will yield.
The difference between the CDI and the Selic
The difference between the CDI and the Selic confuses a lot of people, because the two rates move almost in lockstep. But they play different roles.
Target Selic and Selic over
- Target Selic: set by the Copom (the Banco Central’s monetary policy committee) at each meeting. It is the economy’s benchmark interest rate, used to control inflation. It currently stands at 13.75% a year.
- Selic over: the average rate actually charged on overnight transactions backed by government bonds. It stays very close to the target, usually slightly below.
Where the CDI comes in
The CDI reflects lending between banks, not transactions involving government bonds. Since banks have the alternative of investing in government bonds, the cost of money between them closely tracks the Selic over.
That is why the CDI sits slightly below the target Selic: currently about 13.65% a year versus 13.75%. In practice, when the Copom changes the Selic, the CDI adjusts right afterward.
| Feature | Selic | CDI |
|---|---|---|
| Who sets or calculates it | Copom (target) / Banco Central (over) | B3 (DI rate) |
| Source | Transactions with government bonds | Loans between banks |
| Rate in October 2026 | 13.75% a year (target) | About 13.65% a year |
| Linked investments | Tesouro Selic, poupança | CDB, LCI, LCA, LC, RDB, DI funds |
The CDI today: how much it yields and how it compares
The CDI is currently around 13.65% a year, equivalent to approximately 1.07% a month. The level remains high even after five consecutive Selic cuts, the most recent on September 16, 2026.
CDI vs. poupança
With the Selic above 8.5%, poupança (the traditional savings account) yields 0.5% a month plus the TR (reference rate), around 0.66% a month or 8.2% a year. That is well below the CDI, even though poupança is exempt from IR.
In a simulation with R$ 100,000 over 12 months, poupança would earn about R$ 8,220. A CDB at 100% of the CDI would earn about R$ 11,261 net, after IR. A tax-exempt LCI or LCA at 90% of the CDI would reach about R$ 12,205. The assumption is that rates stay constant, which rarely happens. See the full analysis in is poupança worth it?.
CDI vs. IPCA
The IPCA (Brazil’s official consumer price index) stood at 4.22% over the 12 months through August 2026. With the CDI near 13.65%, anyone investing at 100% of the CDI earns a substantial real return, even after tax. That doesn’t always happen: in periods of low interest rates and high inflation, the CDI can come close to or fall below inflation.
What 100%, 110% or 90% of the CDI means
When an investment promises a percentage of the CDI, it pays that fraction of the rate. In simple terms:
- 100% of the CDI: yields the full rate, about 13.65% a year.
- 110% of the CDI: yields 10% more than the CDI, about 15% a year.
- 90% of the CDI: yields 90% of the rate, about 12.2% a year.
The table below shows approximate figures with the CDI at 13.65% a year, multiplying the percentage by the annual rate. Technically, the percentage is applied to the daily rate, so the annual result ends up slightly higher for percentages above 100% and slightly lower for those below.
| Percentage of the CDI | Approximate gross annual return | Gross return on R$ 10,000 over 12 months |
|---|---|---|
| 85% | 11.49% | R$ 1,149 |
| 90% | 12.21% | R$ 1,221 |
| 95% | 12.93% | R$ 1,293 |
| 100% | 13.65% | R$ 1,365 |
| 105% | 14.38% | R$ 1,438 |
| 110% | 15.11% | R$ 1,511 |
| 120% | 16.60% | R$ 1,660 |
Equivalence between tax-exempt and taxable investments
LCIs and LCAs are exempt from IR for individuals, while CDBs are taxed. To compare them, use the formula: an LCI at X% of the CDI is equivalent to a CDB paying X ÷ (1 − IR rate).
| LCI/LCA (tax-exempt) | Equivalent CDB up to 180 days (22.5% IR) | 181 to 360 days (20% IR) | 361 to 720 days (17.5% IR) | Over 720 days (15% IR) |
|---|---|---|---|---|
| 85% of the CDI | ~110% | ~106% | ~103% | 100% |
| 90% of the CDI | ~116% | ~112.5% | ~109% | ~106% |
| 95% of the CDI | ~123% | ~119% | ~115% | ~112% |
How to calculate what 100% of the CDI yields
Figuring out what 100% of the CDI yields is simple when you follow the market’s logic: the rate is annual, but returns are credited per business day.
Step 1: start with the annual rate
The CDI is published as an annual rate, based on 252 business days. Currently it is about 13.65% a year, or 1.1365 as a factor.
Step 2: convert it to a daily rate
Use the formula: daily rate = (1.1365)1/252 − 1. The result is about 0.0508% per business day.
Step 3: apply the CDI percentage
If the investment pays 100% of the CDI, use the full daily rate. If it pays 110%, multiply the daily rate by 1.10 (about 0.0559% a day). If it pays 90%, multiply by 0.90.
Step 4: arrive at the monthly rate
A month has 21 business days on average. So: (1 + 0.000508)21 − 1 ≈ 1.07% a month. The exact figure varies with the number of business days in each month.
Step 5: calculate the return and deduct IR
Here is an example with R$ 10,000 invested in a CDB at 100% of the CDI for 12 months:
- Gross return: R$ 10,000 × 13.65% = about R$ 1,365.
- IR rate: 12 months equals 365 calendar days, which falls in the 361-to-720-day bracket, with 17.5% IR.
- Tax: R$ 1,365 × 17.5% = about R$ 239.
- Net return: R$ 1,365 − R$ 239 = about R$ 1,126.
To learn the rates for each holding period and other rules, read the guide on Imposto de Renda on investments.
Want to see the same calculation with larger amounts? Check out the simulation in how much R$ 100,000 yields.
Investments linked to the CDI
Much of the fixed income available to individual investors uses the CDI as its index. The main ones are:
- CDB (Certificado de Depósito Bancário): issued by banks, taxed under the regressive table and covered by the FGC (Brazil’s deposit insurance fund).
- LCI and LCA: real estate and agribusiness credit notes, exempt from IR for individuals in 2026, covered by the FGC and usually subject to a lock-up period.
- LC (Letra de Câmbio): a bill of exchange issued by finance companies, taxed and covered by the FGC.
- RDB (Recibo de Depósito Bancário): similar to a CDB, common at digital banks and credit unions, with FGC coverage.
- DI+ debentures: corporate debt securities that pay the CDI plus a spread. They have no FGC coverage.
- DI funds: funds that aim to track the CDI. They are subject to come-cotas (semiannual tax withholding) in May and November and charge a management fee.
FGC coverage is up to R$ 250,000 per CPF (individual taxpayer ID) and per institution, with an overall cap of R$ 1 million every 4 years.
CDI + spread
Some securities, mainly debentures, pay “CDI + X%.” For example, CDI + 2% a year. In this case, the fixed rate is added to the CDI rather than applied as a percentage.
With the CDI at 13.65%, a security paying CDI + 2% would yield around 15.65% a year by simple addition. In practice, the factors are usually multiplied (1.1365 × 1.02), which comes to about 15.9% a year. In exchange for this higher rate, you take on the credit risk of the issuing company, with no FGC guarantee.
The CDI as a benchmark for funds
The CDI is also the main yardstick for comparing investment funds in Brazil. A fixed-income fund that yields less than the CDI, after fees, is not delivering value to its shareholders.
Multimarket and equity funds usually report their performance relative to the CDI or the Ibovespa. If a fund charges a performance fee, check whether it applies only to returns exceeding the CDI.
What happens to the CDI when the Selic falls
Since the CDI tracks the Selic, each Copom cut reduces the return on floating-rate investments. This decline is gradual: what you have already earned is not lost, but future returns become smaller.
The September 14 Boletim Focus (the Banco Central’s weekly market forecast survey) projected the Selic at 13.75% at the end of 2026, 12% at the end of 2027 and 10.5% in 2028. If these projections hold, the CDI is likely to fall by the same amount, always slightly below the target.
Some practical effects:
- Floating-rate CDBs, LCIs and LCAs will yield less over time.
- Fixed-rate investments locked in today may outperform the CDI in the future, if the cuts happen.
- Poupança keeps the 0.5% a month + TR rule as long as the Selic is above 8.5%. Below that, it yields 70% of the Selic + TR.
That is why, during a rate-cutting cycle, many investors combine floating-rate investments for their emergency fund with fixed-rate and IPCA+ bonds for longer-term goals. See how to build this strategy in where to invest in 2026.
Conclusion
Now you know what the CDI is: the rate on overnight loans between banks, calculated by B3 and closely tracking the Selic. In October 2026, it stands at about 13.65% a year, a high level that favors floating-rate fixed income.
When choosing, always compare the CDI percentage, the term, Imposto de Renda and the guarantee. And remember that the CDI is expected to fall if the cutting cycle continues. Follow the Copom’s decisions on the Banco Central website and review your investments periodically.
Frequently asked questions
What is the CDI, in a nutshell?
The CDI is the average rate on overnight loans between banks, calculated by B3. It serves as the benchmark for most fixed-income investments, such as CDBs, LCIs and LCAs.
How much does 100% of the CDI yield today?
With the CDI at about 13.65% a year in October 2026, 100% of the CDI yields approximately 1.07% a month, before Imposto de Renda. R$ 10,000 would earn about R$ 1,126 net over 12 months.
What is the difference between the CDI and the Selic?
The Selic is the benchmark interest rate set by the Copom and reflects transactions with government bonds. The CDI reflects lending between banks. The two move together, with the CDI usually slightly below the target Selic.
Is 110% of the CDI a good return?
For a taxable CDB, 110% of the CDI is an above-average return, but it should be weighed against the term, liquidity and the issuer’s soundness. A tax-exempt LCI or LCA at 90% or 95% of the CDI may yield more, depending on the term.
Will the CDI fall in 2027?
Boletim Focus projections point to a Selic of 12% at the end of 2027. If that holds, the CDI should also fall. But these are projections, not certainties, and they can change at any time.
Can an investment linked to the CDI lose money?
In floating-rate CDBs, LCIs and LCAs guaranteed by the FGC, the risk of loss is low, within the coverage limit. Debentures and DI funds, on the other hand, have no FGC coverage and depend on the health of the issuer or the quality of the fund’s management.
This content is for educational purposes only and does not constitute an investment recommendation. Past performance does not guarantee future results. Data updated in October 2026.