Porque é que a minha ordem de limite de compra não foi executada?

The most obvious reason would be the Spread.

As you may already know, Buy Orders open on the ASK price while Sell Orders open on the BID price.

What you see on the Chart, is the BID price and even though your Buy Limit Price might be visible on the chart, it doesn’t necessarily mean that the ASK price has also reached that level.

Para encontrar o preço ASK, é necessário adicionar o spread que existia nessa altura, mas em todos os casos, o preço ASK será superior ao preço BID.

An easy way to identify the ASK price based on what you see on a Chart is by adding the average spread. This will give you an indication, whether the ASK price reached your Buy Limit level or not.

You can find our Average Spreads here.