Share your opinion and earn yourself a free Motley Fool premium report!

We are looking for Fools to join a 75 minute online independent market research forum on 15th / 16th December.

To find out more and express your interest please click here

Thinking about going all-in on a stock? Here’s why that might not be such a good idea

There are known knowns, known unknowns, and unknown unknowns in investing, which means putting all your eggs in one basket is a bad move.

The content of this article was relevant at the time of publishing. Circumstances change continuously and caution should therefore be exercised when relying upon any content contained within this article.

You’re reading a free article with opinions that may differ from The Motley Fool’s Premium Investing Services. Become a Motley Fool member today to get instant access to our top analyst recommendations, in-depth research, investing resources, and more. Learn More.

You’ve worked hard, kept your cost of living low, saved a good percentage of your salary, and now you want to make your money work for you. If you’re a regular reader of The Motley Fool, you’ll know the benefits of investing in stocks over holding cash: much higher average rates of return and protection against inflation. 

However, there’s a caveat. Higher rates of return tend to come with higher volatility. That means the tendency for prices to fluctuate, and one thing that’s undeniably true of stocks compared to bonds or cash is that their prices tend to fluctuate a lot more. Of course, this is what makes stock investing so potentially lucrative: the possibility of buying something for less than it’s worth. 

Be careful even if you are sure you are right

Due diligence and research are obviously crucial to the process of selecting a good stock for your portfolio. You should never buy a stock without careful examination of all its financial records, and a sober assessment of all the possible things that could happen in its sector and market. But say that you’ve done all of that, and you’ve fallen completely in love with a company. Should you go all in on it? 

Putting all of your eggs into one basket might not be the best idea if you’re someone who gets nervous at the idea of your retirement savings fluctuating. But even if you have nerves of steel, you should think twice about deploying all of your capital in one go. To slightly paraphrase Seth Klarman, a well-known value investor: “Investing requires both arrogance and humility.” You have to be sure enough that you — the buyer — are right and that the seller is wrong, but at the same time, you need to have the humility to recognise that there are limits to even the most thorough research. 

To paraphrase another scholar of the human condition, former US Secretary of Defence Donald Rumsfeld: “There are known knowns, there are known unknowns, and there are unknown unknowns.” Although Rumsfeld was ridiculed for the awkward language of this actually-much-longer speech, I think that investors can learn a lot by adopting this view of the world. 

The biggest risks you face as an investor are not the ‘known unknowns’ that you can anticipate, it’s the ‘unknown unknowns’ that you can’t. In late 2015, who could have foreseen either Brexit or a Donald Trump presidency? 

Diversification is  key

This is the real reason why good investors diversify their portfolios — not because they don’t have confidence in their analysis, but because they understand the practical limits of human knowledge. By buying stocks in a wide range of sectors and geographies, and potentially even adding other asset classes, you can insulate yourself from the volatility that will inevitably come from living in a complex world. If one stock tanks, you don’t lose your entire investment. And besides, there are a lot of high-quality stocks out there, so why limit yourself to just one?

Neither Stepan nor The Motley Fool UK have a position in any of the shares mentioned. Views expressed on the companies mentioned in this article are those of the writer and therefore may differ from the official recommendations we make in our subscription services such as Share Advisor, Hidden Winners and Pro. Here at The Motley Fool we believe that considering a diverse range of insights makes us better investors.

More on Investing Articles

DIVIDEND YIELD text written on a notebook with chart
Investing Articles

Forget high yields? Here’s the smart way to build passive income with dividend shares

Stephen Wright outlines how investors looking for passive income can put themselves in the fast lane with dividend shares.

Read more »

Businessman hand stacking up arrow on wooden block cubes
Investing Articles

15,446 Diageo shares gets me a £1,000 monthly second income. Should I?

Diageo has been a second-rate income stock for investors over the last few years. But the new CEO sees potential…

Read more »

Investing Articles

2 FTSE 100 stocks to target epic share price gains in 2026!

Looking for blue-chip shares to buy? Discover which two FTSE 100 stocks our writer Royston Wild thinks could explode in…

Read more »

A row of satellite radars at night
Investing Articles

If the stock market crashes in 2026, I’ll buy these 2 shares like there’s no tomorrow

These two shares have already fallen 25%+ in recent weeks. So why is this writer wating for a stock market…

Read more »

British Pennies on a Pound Note
Investing Articles

How much money does someone really need to start buying shares?

Could it really be possible to start buying shares with hundreds of pounds -- or even less? Christopher Ruane weighs…

Read more »

Two gay men are walking through a Victorian shopping arcade
Investing Articles

With Versace selling for £1bn, what does this tell us about the valuations of the FTSE 100’s ‘fashionable’ stocks?

Reflecting on the sale of Versace, James Beard reckons the valuations of the FTSE 100’s fashion stocks don’t reflect the…

Read more »

A senior group of friends enjoying rowing on the River Derwent
Investing Articles

Want to stuff your retirement portfolio with high-yield shares? 5 to consider that yield 5.6%+

Not everyone wants to have a lot of high-yield shares in their portfolio. For those who might, here's a handful…

Read more »

Affectionate Asian senior mother and daughter using smartphone together at home, smiling joyfully
Investing Articles

How much do you need in a SIPP to target a £3,658 monthly passive income?

Royston Wild discusses a 9.6%-yielding fund that holds global stocks -- one he thinks could help unlock an enormous income…

Read more »