Term
Bid-ask spread
The gap between the best price someone will pay and the best price someone will sell at. Narrow means liquid and cheap to trade; wide means you lose money the moment you enter.
In pesos: If the best bid is $99.90 and the best ask $100.10, you buy at 100.10 and could only sell at 99.90 right away: 20 cents gone.
Where to go deeper
3/4 6 min Read How a stock exchange actually works What happens between pressing buy and owning a share: the order book, the BMV, its hours, who regulates it, what an index is and what you would see if you walked in.More terms on the same topic
Educational content only: not financial, investment or tax advice. The numbers are examples to understand the idea, not a forecast or a recommendation.