ForecastingStocks

Tesouro Prefixado pays a fixed rate agreed at the moment you buy. If you purchase one yielding 11% per year and hold it to maturity, you know the exact amount you will receive — no surprises from rate moves or inflation.

The appeal and the bet

Locking a rate is attractive when you believe interest rates will fall in the future: you secure today’s higher rate for the life of the bond. In effect, buying a prefixado is a bet that the rate you locked is better than what the market will offer later.

The catch — only certain if held to maturity

The "you know exactly what you’ll get" guarantee applies only if you hold to maturity. If you sell early, the price you get is whatever the market will pay that day, which moves inversely to interest rates:

If rates have risen since you bought, your bond is worth less — you could sell at a loss.
If rates have fallen, your bond is worth more — you could sell at a gain.

This is mark-to-market, and the next lesson explains the mechanism in full.

Variants

Some prefixados pay semiannual interest (juros semestrais / cupom) rather than everything at maturity. These suit someone who wants periodic cash flow, but the coupons are taxed as they are paid, which can reduce the compounding benefit.

When to use it

Consider a prefixado for money you can genuinely leave untouched until its maturity date, when you want certainty about the nominal amount and you judge that today’s locked rate is favourable.