Re: [問題] 美式買權提早執行問題

看板CFAiafeFSA (精算師/基金經理人/銀行家)作者 (well)時間15年前 (2010/10/01 00:07), 編輯推噓1(1013)
留言14則, 3人參與, 最新討論串2/2 (看更多)
我懂你的意思 上面有一條題目 An American call option has a strike price of 50.The risk free rate is 5%. There are 2 months left to expiry.The present value of dividends over the 2 month period is D. Determine the lowerest value of D such that exercising the option early could be rational. 課本:D>K(1-e^-r(T-t))=50(1-e^-0.05*(2/12))=0.414935. 我的想法:D>K(1-e^-r(T-t))+Put(European) 所以根據題目沒辦法算出最小值 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 140.112.230.16

10/01 00:11, , 1F
我想到了 賣權價值為零時有最小值
10/01 00:11, 1F

10/01 00:14, , 2F
但是怎麼確定賣權價值為零啊...orz
10/01 00:14, 2F

10/01 00:15, , 3F
你自問自答...不要想這麼多 D的最小值就是P=0的時候~也就
10/01 00:15, 3F

10/01 00:15, , 4F
是 could be ration 一定要有的條件 PV... " > " K ...
10/01 00:15, 4F

10/01 00:16, , 5F
如有講解不清 麻煩ysc 帥哥幫我補充一下!!!
10/01 00:16, 5F

10/01 00:18, , 6F
我覺得不能直接設賣權為零耶
10/01 00:18, 6F

10/01 00:18, , 7F
除非它有說the possible lowest value
10/01 00:18, 7F

10/01 00:21, , 8F
rational 的必要條件就是PV ... > K... 所以...
10/01 00:21, 8F

10/01 00:22, , 9F
帥哥他說: manual 寫得很清楚喔>.^
10/01 00:22, 9F

10/01 00:24, , 10F
rational的必要條件應該是PV()>K()+P?
10/01 00:24, 10F

10/01 00:28, , 11F
yeap! lowest value ... could be rational
10/01 00:28, 11F

10/01 02:41, , 12F
合理的條件只有股利的現值 > 利息的現值喔
10/01 02:41, 12F

10/01 02:43, , 13F
也就是 D>K(1-e^-r(T-t)) 跟Put沒關係的
10/01 02:43, 13F

10/01 02:45, , 14F
上面的D 是你這題假設的 也就是股利的現值
10/01 02:45, 14F
文章代碼(AID): #1CfBNRvw (CFAiafeFSA)
文章代碼(AID): #1CfBNRvw (CFAiafeFSA)