Final answer:
The minimum initial purchase requirement for 100 shares at $15 each would typically be $750 in a margin account due to 50% margin requirements, or $1,500 in a cash account where the full amount is required upfront.
Step-by-step explanation:
The minimum initial requirement when purchasing 100 shares at $15 in a new account is typically governed by the brokerage's margin requirements or by regulatory requirements such as the Federal Reserve Board's Regulation T, which generally requires an initial investment of at least 50% of the purchase price in a margin account. Therefore, in this case, the minimum initial investment would be $750 (100 shares x $15 per share x 50%). This assumes the purchase is being made on margin and does not consider any potential brokerage fees or commissions that may apply. For a cash account, the full purchase price would typically be required upfront, which would be $1,500 (100 shares x $15 per share).