If you dont have the money to cover it then obviously you cant buy. Some accounts are on margin which means you are taking loans to buy if not enough money, so you owe that plus interest.

Can you owe money in stocks?

For example, if I have ￡100 in my trade account and I want to place an order for 2 shares, where the required securities are ￡12 but the value of the 2 shares are ￡1800, can I afford to buy that?

Would I need to have in my trade account the ￡12 (required security) or ￡1800 (the value of the 2 shares) or ￡1812 (the sum of the required security _ the value of the 2 shares)?

If the shares for that particular order/company were to go bust, what would be the most amount of money I could lose?

I'm using Plus500 WebTrader, but I'm assuming the principal is the same for others too?

Thanks.