margaretzhou

Day 0: initial margin acct. bal.: 10*5=50

 

Day 1: price increases to 103, so acct. balance has to decline 3*10=30 (price increases gets loss for short position), ending balance 20<30(maintenance margin requirements)

 

Day 2: margin acct. bal. increases to 50

          price decreases to 96, so balance has to increase (103-96)*10=70, ending balance 120>30

 

Day 3: margin acct. balance 120

          price increases to 98, so balance has to decrease 2*10=20, ending balance 100.