"Margin of Safety" as the Central Concept of Investment

在工廠做工的人知道﹐工廠的四週圍貼著“安全第一”﹑“注意安全”的標語﹐因為員工出意外是大事。工廠發生了鬧出人命的工業意外﹐除了造成全體員工士氣低落﹐也會惹上官司。

父母關心孩子﹐出門前總是千交代萬交代﹐要注意自身的安全﹐別魯莽行事。

但是﹐有誰人在股票交易所的大廳見過“安全第一”﹑“注意安全”的標語﹖
買入股票之前考慮過安全﹖


“The Intelligent Investor” 最後一篇﹐Graham說投資的核心原則就在于安全第一。
根據我對這一篇的了解﹐我認為必需完成四個步驟﹐才算是安全﹐才算是投資。

投資安全的第一步﹕

守舊的人買入債券是為了收息﹐雖然他無法準確的預測公司的前景﹐不過他可以選擇很多年以來顯示利息擔保(interest coverage)足夠的公司﹐就算將來景氣不好﹐這家公司很大可能會履行義務支付債券利息。

同理的﹐買股票正確的方法也應該和債券相同。
無法履行義務支付貸款利息的公司已經等同破產﹐投資者得到的是損失。

所以第一步﹐你的投資標別破產(除非投資目的是損失)。


投資安全的第二步﹕
Graham﹕
Bond:
If the margin is a large one, then it is enough to assume that future earning will not fall far below those of the past in order for an investor to feel sufficiently protected against the vicissitudes of time.

If the business owes $10 million and is fairly worth $30 million, there is room for a shrinkage of two-thirds in value(at least theoretically), before the bondholders will suffer loss.

Since average stock price are generally related to average earning power, the margin of “enterprise value” over debt and the margin of earnings over charges will in most case yield similar results.

Common stocks:
There are instances where a common stock may be considered sound because it enjoys a margin of safety as large as that of a good bond.

When a company has outstanding only common stock that under depression conditions is selling only for less than the amount of bonds that could safely be issued against its property and earning power.

In such instances the investor can obtain the margin of safety associated with bond, plus all the chances of larger income and principal appreciation inherent in a common stock.

Common stock bought under such circumstances will supply an ideal, though infrequent, combination of safety and profit opportunity.

chief losses to investor come from the purchase of low quality securities at time of favorable business conditions.

所以第二步﹐ 價值/價格分離的空間要夠大才算安全﹐小的不算﹐而且經過標準檢驗都能合格。


投資安全的第三步﹕
There is a close logical connection between the concept of a safety margin and the principle of diversification.

Even with a margin in the investor's favor, an individual security may work out badly.

For the margin guarantees only that he has better chance for profit than for loss--not that loss is impossible.

當我們談到買廉價股時﹐強調集體操作就顯得重要了﹐許多錯誤可能會相互抵消﹐等于置身于大家熟知的保險形態的操作。


所以第三步﹐在自己的能力圈內多樣化﹑分散持有證券。


投資安全的第四步﹕

“投資操作是經由透徹的分析﹐以確保本金的安全及滿意的獲利﹐凡不合這些條件的操作方式都算是投機”

在投機的操作中﹐你無法透過證券分析的過程﹐來預測到成功的結果。這並非表示投機絕對不會成功﹐而是你無法僅透過遵循我們的證券分析方法﹐就可以在許多個案中成為成功的投機者。

We say that to have a true investment there must be present a true margin of safety. And a true margin of safety is one that can be demonstrated by figures, by persuasive reasoning, and by reference to a body of actual experience.

所以第四步﹐能區分投資與投機。


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總結﹕

我研究並且實行Graham的證券分析方法﹐並非羨慕巴菲特的驚人財富﹐夢想終有一日能如此。

我是希望在我喜愛﹑充滿興趣的股票投資工作中得到樂趣﹐在將來的日子得到滿意的回報﹐改善生活品質﹐在生命結束之前沒有遺憾。

There is no guarantee that this fundamental quantitative approach will continue to show favorable results under the unknown conditions of the future. But, equally, there is no valid reason for pessimism on this score.

我認為有這樣的承諾已經是很足夠的了。