Diversification could boost your investment returns… or it could damage them!

Is diversification such a good idea? It can be a double-edged sword.

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.

When faced with the idea of investing all their long-term savings in shares, most people would probably react in horror. A stock market crash would wipe you out, wouldn’t it?

That thinking has created the profitable business of asset allocation — profitable to those who manage investments, that is. This amount in shares, so much in gilts, another portion in company bonds… you know the idea.

Set against that we have the Barclays equity-gilt study, which shows that shares have been the best performing investment from 1899 to 2016, beating cash in a savings account in 91% of all rolling 10-year periods. Extended to 18-year periods, shares have won 99% of the time. And over 23-year periods, cash has never beaten shares.

If you have an investing horizon of 20 years or more, you’ve almost certainly got more to lose from inferior performance and management fees by diversifying into all sorts of other investments, than if you stick with shares.

A mixed bag of funds?

Having decided on the stock market, many folk then turn to managed funds and start fretting over diversifying those. How much should I put into UK income? Emerging markets? Small-cap growth? There are funds of funds, which do the diversification into different individual funds for you… but that just adds another level of management charges.

I’d say all that diversifying into different funds achieves is the increasing likelihood that you won’t even match a FTSE 100 index tracker. In fact, there are very few investment managers who can beat the FTSE in the long term — I can think of Warren Buffett and our very own Neil Woodford, but then I’m scratching my head.

If you really want a fund, I’d say go for an index tracker and forget fund diversification.

Individual shares

When we choose and buy our own shares, using a low-cost execution-only broker, we’re finally coming to a stage when diversification does make sense. But even then, it still comes with qualifications.

I certainly wouldn’t put all my money into one stock, because even with those that look safe we can hit a catastrophe that sends them crashing. So spreading your investments across different sectors can definitely help — if only, say, 5% or 10% of your portfolio had been in banking shares, the financial crisis would still have hurt, but relatively lightly.

A well-diversified portfolio can be put together from just our top FTSE 100 shares. A big oil company like BP or Royal Dutch Shell, one of the major banks, GlaxoSmithKline or AstraZeneca from the pharmaceuticals sector, utilities provider National Grid, consumer goods giant Unilever… and you already have the makings of a well-diversified portfolio (without paying anyone a penny to do it for you).

Different methods

Another approach is to diversify by strategy, for example, holding a number of safe dividend-paying shares and then putting some of your money into riskier (but potentially more rewarding) growth candidates.

Or spread your money by market capitalisation, with some invested in very large companies and some in smaller cap firms.

The choice of strategy is yours alone, but there’s one rule that I always stick to. I will only ever invest in a share that I genuinely think is a great investment. If I wouldn’t buy on its standalone merits, I’d never buy a share just to diversify — that’s di-worse-ification

Alan Oscroft has no position in any shares mentioned. The Motley Fool UK owns shares of and has recommended GlaxoSmithKline and Unilever. The Motley Fool UK has recommended AstraZeneca, Barclays, BP, and Royal Dutch Shell. 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

Calendar showing the date of 5th April on desk in a house
Investing Articles

Investors are rushing to buy these before the Stocks and Shares ISA deadline. Should we join in?

Despite geopolitical troubles causing so much pain in the world, Stocks and Shares ISA investors in the UK are keeping…

Read more »

Mature friends at a dinner party
Investing Articles

How much do you need in a Stocks and Shares ISA for a £10,000 second income?

Ben McPoland highlights a FTSE 100 dividend stock yielding 7% that could contribute nicely to an ISA generating a second…

Read more »

Close-up of a woman holding modern polymer ten, twenty and fifty pound notes.
Investing Articles

How big a Stocks and Shares ISA is needed to target £500 of monthly passive income?

Christopher Ruane explains how a Stocks and Shares ISA could potentially earn someone thousands of pounds in dividends per year.

Read more »

British pound data
Investing Articles

With the stock market down, here are 2 potential ISA bargains to consider right now

When the stock market dips, investors looking at long-term prospects should seek out cheap shares, right? I have my eye…

Read more »

Mature black woman at home texting on her cell phone while sitting on the couch
Investing Articles

Want a £1m Stocks and Shares ISA? Step 1 starts before 5 April

Dr James Fox explains why the Stocks and Shares ISA is an incredible vehicle, and why investors may want to…

Read more »

Happy woman commuting on a train and checking her mobile phone while using headphones
Investing Articles

2 dirt-cheap stocks to consider buying for an ISA portfolio in April

This pair of UK shares are down by double digits in recent months. Ben McPoland sees both as stocks to…

Read more »

Front view photo of a woman using digital tablet in London
Growth Shares

I think this undervalued penny stock has serious potential to outperform

Jon Smith points out a penny stock that's started to rise as the company pushes ahead with a transformation that…

Read more »

Close-up of children holding a planet at the beach
Investing Articles

2 dividend-paying investment trusts to consider for a Stocks and Shares ISA

These two London-listed funds source their dividends globally, offering income investors diversification inside an ISA portfolio.

Read more »