After learning about initial and maintenance margin I have some questions that I could not find answers too. An account with $50,000 cash has $100,000 buying power. Upon buying $100,000 of stock how is maintenance margin calculated. Browsing the forums it seemed people have used $50,000 4:1 to buy $200,000 of stock. Is this only possible if there is enough cash left to satisfy the margin requirement? Overall Id like clarification on how initial and maintenance margin in used. Thank You