追加保證金問題

希望對這個問題的一部分進行解釋：

Execute a margin call of 1000 shares of a stock at $40/share.
The initial margin requirement is 50% and the maintenance margin
requirement is 30%.

I hold for one year, at which time the stock is selling for $50/share
and the stock paid a dividend of $1. The interest rate on the loan was 6%
annually.

Calculate the percentage return on investment.

我會使用的公式是：

R(t) = [P(t) - P(t-1) + D(t) - Interest(t)] / Initial Investment

我知道答案是：

[50 - 40 + 1 - 1.2] / 20 = 49%

但我不明白為什麼利息是 1.2 而不是 0.06。這背後的原因是什麼？

初始頭寸價值 40000。您發布 50% 的保證金，因此您存入 20000 並藉入 20000。20000 的 6% 是 1200。

引用自：https://money.stackexchange.com/questions/37620