3 wealth-destroying investing mistakes I’d avoid

Here’s one way to help keep your portfolio in good health.

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.

If you invest in the shares of individual companies, I reckon it’s important to keep a close eye on them. Single-company shares have the potential to outperform the general market indices, but they can also underperform.

And I think one of the most important ingredients of successful investing is to protect your portfolio from big drawdowns if you can. “Don’t lose money,” Warren Buffett urges us. And one way of guarding against big losses is to sell shares when you realise you’ve made a mistake.

Warren Buffett did that with his investment in Tesco a few years back. The share price moved against him and he realised he’d lost his confidence in the firm’s management. So he sold his entire holding for a loss of millions. But his loss could have been larger still if he’d held on to the declining shares.

Well-known British investor Lord John Lee told us he’d introduced a stop-loss rule to his strategy in recent times, set at about 20%. If he buys a share and it moves the wrong way, he’ll cut the loss at 20% or so and acknowledge that he made an error. And investor/traders such as Mark Minervini have been banging the drum for years about their strict stop-loss strategies.

Here are three wealth-destroying investing mistakes I’m determined to avoid in 2020 and beyond.

1. Not cutting losses

It’s always tempting to hold onto shares after we’ve bought them even when they start to slide. One of the big fears is they may turn around and shoot back up as soon as we sell out.

But not stopping a loss by selling can sometimes have big financial consequences. For example, Pharos Energy has looked good on paper to many investors for a long time, but the shares have declined by more than 90% over the past six years.

Cutting the loss early would have been a good idea in the case of Pharos Energy. And because we can’t tell which shares will recover and which ones will continue to plunge, for me, the best idea is to always cut losses.

2. Averaging down

Some investors buy more shares in a company if the price moves against them. But if you do that you are really betting that the shares will rise again based on your own assessment of the fundamentals and prospects for the business.

Consider this, though. You’ve already completed a purchase based on your opinion and have been proven ‘wrong’. If you repeat the process you could be wrong again and end up increasing your losses. I reckon the safest approach for me is to never average down on a losing share.

3. Catching falling knives

Investing in falling share prices – or falling knives as many have become known – usually involves taking a contrarian view about a company experiencing difficulties of some kind. But such an approach means you’re hoping for an operational recovery in the underlying business. And it’s easy to be wrong in your assessment, so I’d avoid these types of situations altogether.

Kevin Godbold has no position in any share mentioned. The Motley Fool UK has recommended Tesco. 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

Concept of two young professional men looking at a screen in a technological data centre
Investing Articles

Here’s why I’m betting big on these 2 FTSE 100 stocks in the age of AI

This pair of FTSE 100 stocks couldn't be more different. So why are they big positions in my Stocks and…

Read more »

UK financial background: share prices and stock graph overlaid on an image of the Union Jack
Investing Articles

Is last week’s dip in the Rolls-Royce share price a brilliant buying opportunity?

Even the Rolls-Royce share price can't shake off current stock market turmoil, but Harvey Jones says the FTSE 100 stock…

Read more »

Senior Adult Black Female Tourist Admiring London
Investing Articles

Does the Lloyds share price suddenly look like a bargain again?

After a brilliant run the Lloyds share price was starting to look a little overstretched, says Harvey Jones. But does…

Read more »

British pound data
Investing Articles

It’s time to prepare for a stock market crash

Edward Sheldon expects the stock market to keep rising in 2026. However, looking further out, he sees the potential for…

Read more »

DIVIDEND YIELD text written on a notebook with chart
Investing Articles

£5,000 buys 1,938 shares in this 8.4%-yielding passive income stock!

An investment of £5,000 in this amazing passive income stock could generate £422 in dividends this year. And things could…

Read more »

Night Takeoff Of The American Space Shuttle
Investing Articles

A red-hot UK growth name to consider buying in a Stocks and Shares ISA

With exposure to data centres, defence, and nuclear power, is Avingtrans an under-the-radar steal for a Stocks and Shares ISA?

Read more »

Businessman hand stacking up arrow on wooden block cubes
Investing Articles

Meet the FTSE 250 firm that’s averaged 32% annual growth since 1982

The FTSE 250's home to one of the UK’s most impressive growth stories. But while it owns well-known brands, most…

Read more »

ISA coins
Investing Articles

How much do I need in an ISA to aim for a £500 monthly second income?

Looking to unlock a chunky second income from an ISA within 10 years? James Beard explains how this might be…

Read more »