单选题 An analyst does research about margin transaction. An investor purchases a stock priced at $80 by borrowing the maximum amount under a 65% initial margin requirement. If the maintenance margin requirement is 30% the security price below which the investor will first receive a margin call is closest to:
A. $37
B. $40
C. $52

【正确答案】 B

【答案解析】[解析] 需要追加保证金时股价的公式为：margin call price=P₀×(1-initial margin)/(1-maintenance margin)，且P₀=initial purchase price。
因此，需要追加保证金时的股价=$80×(1-65%)/(1-30%)=$40。