Investing Basics: What does Margin of Safety mean?

Friday, Jan 27 2012 by
Investing Basics What does Margin of Safety mean

“To have a true investment, there must be 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.” 

When celebrated value investor Benjamin Graham set out his thinking on why and when to purchase stocks in his influential 1934 book Security Analysis, his insistence on having a Margin of Safety was a key factor. Years later, Graham’s student Warren Buffett described the phrase as the "three most important words in investing". But what does it mean and, more importantly, how do you make sure you have got one?

What is a Margin of Safety?

Margin of Safety is a term that is more or less owned by value investors, whose central aim is to buy stocks that they believe are undervalued by the market. Value investors apply relentless scrutiny to stocks in an effort to stand apart from the crowd and they do it by figuring out what they believe to be a company’s intrinsic, or “true”, value and then comparing that to what the rest of the market believes (read more about how investors value stocks).

The difference between the market price and the intrinsic value is the Margin of Safety. If the shares of a company currently trade for 75p, but the intrinsic value of the shares is £1.00, then the Margin of Safety would be 25%. Given that the investor is using his own judgement, the technique introduces a cushion against capital loss caused by an error of judgement or unpredictable market movements (i.e. the value of the stock falls further). Buffett described the margin of safety concept in terms of tolerances:

“When you build a bridge, you insist it can carry 30,000 pounds, but you only drive 10,000-pound trucks across it. And that same principle works in investing.”

Opinions are divided on how large the discount needs to be to qualify the stock as a potential “buy”. Indeed, the bad news is that no-one really agrees on this – for two reasons. First, determining a company’s intrinsic value is highly subjective. The way that Benjamin Graham calculated margin of safety years back was highly asset/NCAV-based, and probably quite different from how analysts/investors might today  make the calculation. Second, investors are prepared to wear different levels of risk on a…

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As per our Terms of Use, Stockopedia is a financial news & data site, discussion forum and content aggregator. Our site should be used for educational & informational purposes only. We do not provide investment advice, recommendations or views as to whether an investment or strategy is suited to the investment needs of a specific individual. You should make your own decisions and seek independent professional advice before doing so. Remember: Shares can go down as well as up. Past performance is not a guide to future performance & investors may not get back the amount invested. ?>

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6 Comments on this Article show/hide all

UK Value Investor 28th Jan '12 1 of 6

For me the Margin of Safety is a direct consequence of my favourite three words in investing:


That is the basic premise that I build any investment case on and many aspects of Margin of Safety flow directly from now knowing:

I don't know what the economy is going to do - so buy businesses that are likely to survive recessions and prosper afterwards (low debt, consumer non-durables, etc etc).  Also prefer international businesses because the economic future of any one geographic area is also highly uncertain.

I don't know which industries are going to do well - so diversify across many industries.

I don't know what any one company is going to do - so diversify across 20 or 30 or more different ones.

I don't know whcih companies are going to survive in any given industry - so prefer those that are already in industry leading positions, those that are in the "big 5" or whatever.

I don't know what inflation's going to do - so try to buy stocks that have some chance of increasing prices in line with inflation.

And there are many more.

I think that the more you can understand how much you don't know, the better off you are because you look for that Margin of Safety (in all its varied forms) precisely because you realise how little you actually know. 

Blog: UK Value Investor
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Edward Croft 28th Jan '12 2 of 6

In reply to post #63637

I don't know if I don't know is a good investment philosophy!  One of my favourite Buffett quotes is...

"I put a heavy weight on certainty. If you do that then the whole idea of a risk factor doesn't make any sense to me.  You don't invest where you take a significant risk... its not risky to buy securities at a fraction of what they're worth."

I think the problem is that this whole industry puts a heavy weight on doing something all the time which is never a good investment philosophy!  The truth is that the best trade is often no trade at all.  Again as the quotable one would say 'You have to wait for the fat pitch'.

For me the idea of owning 30 self-picked stocks isn't a practical one for a couple of reasons.

  •  Firstly by owning 30 stocks you are really just building an expensive index substitute with a high tracking error.   
  • Secondly, there's a massive time investment in researching and committing to those 30 stocks, which is an opportunity lost elsewhere in your life !

I think there's a more sensible solution for investors who love to pick stocks.  If you do feel you need to be invested, why not buy a tracker for the majority of your portfolio but leave a comfortable percentage to indulge in stock picking for alpha with a handful of seriously high probability bets?  

Granted -  high probability bets with a big margin of safety do not happen very often - but when they do, one should be able to act with certainty and act decisively.

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UK Value Investor 30th Jan '12 3 of 6

In reply to post #63638

Using a small part of a portfolio as 'play money' or 'alpha money' is probably a good fit for a lot of people. Obviously I'd disagree that this is more sensible than hand picking 30 high quality high value stocks, but we all have our different approaches and they can all co-exist peacefully!

Blog: UK Value Investor
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Lepep 24th Dec '16 4 of 6

Good value very good jargon free clear explanation.

" How can we ensure a Margin of Safety" and Caveats provides the steps required to an analyse and put into practice process required to use in your personal Share investing


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MichaelMasters 18th Jun '18 5 of 6

I seem to have committed nearly everything 'crime' in the book by not spending time researching enough.
i am now trying to do better!

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mmarkkj777 18th Jun '18 6 of 6

I know this is an old article, but its a great article and sound advise for the careful investor (which we should all be with the bulk of our capital).

Ben Graham was my first Guru (others later added to my thinking and my approach, but I'm fundamentally a Value Investor at heart). But I recommend the Intelligent Investor (also Ben Graham and still available) as an easier read for most people.

I agree with Ed that 30 shares (as UK Value Investor suggested in his post above) is too many to manage. In my opinion it would be like looking after 30 kids in a house. While you have your eye on one group, another could be reaping havoc.
Also, if you select, for safety, diversification in sectors, top companies from each sector, inflation proof earners, etc, etc. as suggested, your results would probably be similar to the market anyway, so why not a tracker.
My own approach is to let others invest a large proportion of my capital (e.g. Giles Hargreaves at Malborough, Mark Slater, etc. You know, the ones who have historically done better than the market). We know that past performance is no guarantee, but its probably still better than any other method ever thought of.
Also, if you then compare your performance to theirs, It also serves as a good guide as to if you are really investing well, or if you should leave it to the experts and just invest pocket money for fun.

As an aside, another metric I like is ROCE. What are they doing with the retained profits. Are they really using it well to increase the future value and earnings in the company? It seems to be less thought about than some of the other measures, but can be a good indicator of future price increases.

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