...Sang Won Hwang I estimate that a margin as trading frictions has an effect on the strategies of writing options. The important results are as follows. First, by the margin requirement is increased, the size of short position is reduced. Second, the discrimination of a margin requirement is due...

...Hak-Kyum Kim; Jinwoo Park Margin requirements are often viewed as an effective policy tool to prevent the default risk and maintain market stability. For the Korean futures market, this paper examines whether the margin requirements work normally as a tool to prevent default risk and margin changes...