Question 1

How does Datafindex convert annual rates to monthly rates?

Accepted Answer

We use the compound equivalent rate equation: i_m = (1 + i_a)^(1/12) - 1. We avoid simple division by 12, as linear division neglects compounding and skews financial accuracy.

Question 2

What is the difference between beginning vs end of period contributions?

Accepted Answer

Contributions made at the beginning of the period earn interest in that very same month (annuity due). Contributions made at the end of the period start earning from the subsequent period onward (ordinary annuity).

Question 3

How does regressive fixed income taxation work?

Accepted Answer

In Brazilian fixed income, investments follow Law 11.033/2004: up to 6 months 22.5%; 7 to 12 months 20.0%; 13 to 24 months 17.5%; and above 24 months 15.0%. Taxes apply exclusively to earned interest.