I'm trying to understand the logic of RegT margin accounts.
Let's assume that I have a $10,000 account and I purchase stock XYZ worth $5,000.
Will my broker automatically give me a loan of 50% (=2,500) for that position, so that I have a debit balance of 2,500? Or, because I have enough money, will I pay the full price for it without borrowing money?
In other words, do I always borrow money from my broker when buying a stock in a margin account?