A gap on the screen isn't a profit

I do arbitrage between Argentine pesos, US dollars, euros, crypto and stablecoins, on exchanges and in P2P markets. The idea is easy to explain: the same thing isn't worth the same everywhere, and sometimes that gap can be taken.

The problem is that the gap is the first thing you see, and it isn't what you keep.

From the gap to what's left

Between buying in one place and selling in another there are steps: converting from one currency to another, moving from one market to the next, paying fees. Every step costs something. A gap that looks good on the screen can leave nothing once you add it all up, or a lot less than it seemed.

Then there's execution: whether the trade can actually go through, under the conditions you were looking at when you did the math.

Why a spreadsheet

That's why every trade goes through an Excel spreadsheet with formulas. I put in the prices, the cost of each step and what's left at the end. The decision comes out of that math, not out of gut feeling or arithmetic in my head.

With one step, mental math is enough. With several currencies and markets in between, a formula never forgets a cost; I might.

Over time, that spreadsheet became a way of working I repeat on every trade: the same structure, the same formulas, different prices. How I got here, starting with my first crypto at 11, is in Markets.

What I take from it

• —The price gap is the starting point, not the result.
• —Every step has a cost, and you have to count all of them before deciding.
• —You don't need to guess where the price is going. You need to get the math right.