The Tamias Blog

The Perfect Coupon Timing Is Worth R$ 116 (and You Still Can't Capture It)

July 17, 2026 · 10 min read

There's an elegant optimisation hidden in the regressive tax table: buy on the right date so the first coupon dodges the priciest bracket. We ran the numbers. It's a mirage — and the mirage teaches more than the result.

Reinvest or Spend: The Question That Decides Between Coupon and Zero-Coupon

July 17, 2026 · 10 min read

The fight between a coupon bond and a zero-coupon one isn't settled by watching interest rates. It's settled by a question about you: will the money this bond produces go back to earning, or become an expense? The answer inverts everything.

The Tax You Don't Pay Today: Why Deferral Is a Source of Return

July 17, 2026 · 10 min read

Most investors compare tax rates. Almost nobody compares the timing. But when you pay tax changes your return as much as how much you pay — and over a retirement horizon, deferral is worth more than a point a year.

The High-Coupon Myth: Why Getting Paid Sooner Doesn't Mean Earning More

July 15, 2026 · 12 min read

The semiannual coupon is sold as passive income and a clear advantage. It is really a risk swap — and for anyone still in the accumulation phase, an expensive one: the taxman collects even when interest rates never move.

Does the 4% Rule Work in Brazil?

May 18, 2026 · 10 min read

The most famous rule in retirement planning was built on American data from 1994. Brazil has a different inflation history, thinner market data, and some of the highest real interest rates on the planet. Applying the same number could be a costly mistake.