saw a post on X from suno investimentos with tiago guitián reis saying 97% of brazilians dont know what the compound interest formula means, and concluding: "thats why we are a poor country."
the formula is this:
- M = C * (1+n)^t
where:
- M = final amount (how much ull have)
- C = initial capital (how much u put in today)
- n = interest rate per period
- t = time in periods
the intention behind the post is clear, if more brazilians understood compound interest theyd make better financial decisions. not a bad idea, and spreading financial education is a genuinely legit goal.
but theres a problem with the argument. and its hidden inside the formula itself.
where the argument breaks
the formula works great. the problem is the "thats why" in the sentence.
saying brazil is poor because ppl dont know compound interest is reversing causality. the actual relationship is more or less the opposite, its hard to learn and practice advanced finance when the month doesnt close.
for the formula to do anything, u need a positive and relevant C. without initial capital to invest, the equation never takes off.
u can know by heart all the fixed income theory, CDB, treasury direct, stocks, REITs... but if at the end of the month u have R$ 0 left after rent, electricity, food and transport, the formula doesnt change much. (¬_¬)
but financial education isnt useless
no! far from it.
knowing not to fall for financial pyramids, understanding credit card revolving traps, not financing a fridge in 48x without thinking, avoiding unnecessary payroll loans... that makes a real concrete difference for any income bracket.
so yeah, spreading compound interest is useful. the problem isnt the formula, nor the intention of whoever spreads it.
the problem is using this to explain poverty, as if it were a matter of mathematical ignorance from the people. that reading ignores decades of structural inequality and puts the weight in the wrong place.