问题如下：
A company has 1 million shares outstanding and earnings are £2 million. The company decides to use £10 million in idle cash to repurchase shares in the open market. The company’s shares are trading at £50 per share. If the company uses the entire £10 million of idle cash to repurchase shares at the market price, the company’s earnings per share will be closest to:
选项：
A.£2.00.
B.£2.30.
C.£2.50.
解释：
C is correct.
At the current market price, the company can repurchase 200,000 shares (£10 million/£50 = 200,000 shares). The company would have 800,000 shares outstanding after the repurchase (1 million shares − 200,000 shares = 800,000 shares).
EPS before the buyback is £2.00 (£2 million/1 million shares = £2.00). Total earnings after the buyback are the same because the company uses idle (nonearning) cash to purchase the shares, but the number of shares outstanding is reduced to 800,000. EPS increases to £2.50 (£2 million/ 800,000 shares = £2.50).
这道题没有提到闲置资金如果不做回购还会有另外的收益，所以不考虑，假定earning在回购前和回购后都是不变的。
我还想再问一个问题：
老师提到，当用cash回购股票时，若earning yield大于after-tax yield of fund，则回购划算，eps上升；若earning yield小于after-tax yield of fund，则回购不划算，eps下降。但是当小于时，由于股数是下降的，而EARNING也是下降的，是不是eps还不好判断会不会下降？
当用debt回购股票时，我也有相同疑问。即当判断回购不划算时，Eps的方向如何判断？
