NO.PZ201512181000007304
问题如下:
Based on Exhibit 2, the average effective spread of the three trades is closest to:
选项:
A.$0.0333.
$0.0367.
$0.0400.
解释:
C is correct. The effective bid–ask spread for buy orders is calculated as:
Effective bid–ask spread (buy order) = 2 × {Trade price – [(Ask price +Bid price) / 2)]} or
= 2 × (Trade price – Midpoint of the market at the time an order is entered).
So, the effective bid–ask spreads for the three buy trades are calculated as:
Effective spread of Trade 1 = 2 × {$25.20 – [($25.20 + $25.17)/2]} = $0.0300.
Effective spread of Trade 2 = 2 × {$25.22 – [($25.22 + 25.19)/2]} = $0.0300.
Effective spread of Trade 3 = 2 × {$25.27 – [($25.26 + $25.22)/2]} = $0.0600.
The resulting average effective spread is then calculated as:
Average effective spread = (Effective spread of Trade 1 + Effective spread of Trade 2 + Effective spread of Trade 3)/3.
Average effective spread = ($0.0300 + $0.0300 + $0.0600)/3 = $0.0400.
老师 想确认一下公式
effective spread的计算公式,答案解释里面,是2*(trade price-(bid price+ask price)/2)。老师上课说的是2*(trade price-mid quote)
而mid quote=(inside ask+inside bid)/2。 inside ask和inside bid,是指的best ask和best bid
所以我有点疑问,这里到底应该是用best ask/bid,还是直接用ask/bid price就可以?
如果是best ask/bid, 这道题应该只有一个best ask/bid,而不是答案解析里面用每一次的ask/bid。
请老师帮忙确认一下这个公式到底是怎么计算呢?谢谢!