Diluted EPS

A performance metric used to gauge the quality of a company’s earnings per share (EPS) if all convertible securities were exercised. Convertible securities refers to all outstanding convertible preferred shares, convertible debentures, stock options (primarily employee based) and warrants. Unless the company has no additional potential shares outstanding (a relatively rare circumstance) the diluted EPS will always be lower than the simple EPS.[1]

Diluted earnings per share (Diluted EPS) takes the basic earnings per share figure one step further. Basic EPS only takes into account the number of shares outstanding at the time. Diluted EPS, on the other hand, estimates how many shares could theoretically exist after all stock options, warrants, preferred stock and / or convertible bonds have been exercised. The theory goes that because some or all of these investments could be converted or exercised, the number of shares outstanding could increase at any time. This reduces the amount of a company’s earnings each share is entitled to. In doing so, the price to earnings ratio becomes higher, and the stock appears more expensive. In most cases, the diluted earnings-per-share figure is far more accurate estimation of the total earnings per share and receive special attention when valuing a company. [2]

關鍵就在上市公司發行的有價證券，除了普通股票之外，公司發行在外的有價證券還可能包括可轉換債券、優先股、股票選擇權(通常主要是發行給員工)，以及認股權證同時行使權利等等。

每股盈餘由股東應得獲利(attributable profìt)除以發行在外總股得出，是評估上市公司盈餘能力的一項指標，在計算每股盈餘時也要將普通股票之外的其他有價證券可能會影響到再增加發行普通股一併計入，其所得就是稀釋後的每股盈餘，此數值一定低於基本每股盈餘。

解釋：認股權證、股票選擇權、可轉換債券或優先股，都可能讓公司發行更多普通股，因而稀釋了每股盈餘，這對股東來說，自然不是好事。不過，稀釋後每股盈餘是較保守的指標，因為它假設所有可轉換為普通股的證券同時行使權利，而這轉換也可能實際上不會發生，不過如果公司表現出色，這些證券的確會陸續行使權利。稀釋後每股盈餘若大幅低於基本每股盈餘，就代表現有股票的權益可能遭明確稀釋，這幾乎是所有分析師與投資人不樂見的情況。