3 basic but costly ISA mistakes to avoid

This writer is trying to avoid a trio of mistakes that people commonly make with a Stocks and Shares ISA. Here’s why he wants to steer clear of them.

| More on:

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.

ISA coins

Image source: Getty Images

A Stocks and Shares ISA can be a powerful platform for building wealth over the long term, even from a modest base.

But while rising share prices and dividends could help to create wealth in an ISA, there are also factors that can destroy it.

That is why I try to avoid this trio of common traps when investing.

Getting too excited about one share

Imagine this scenario.

You buy a share you think is brilliant and it goes up a lot. So you buy more – and it goes up further. Excited, you buy even more – and it goes up again.

This is both bad and good, in my view. Clearly the increase in value is good – so what’s bad? The lack of diversification in the ISA.

More and more money being put into one share makes the ISA less diversified. Meanwhile, that share’s rising value means it comes to represent a larger and larger percentage of the overall portfolio.

That can happen to anyone – Warren Buffett’s Apple stake came to dominate his portfolio at one point precisely because the price had risen so far.

Buffett then sold lots of Apple shares, although by hanging on to many he suggested that this was not because he had lost faith in the investment case.

No matter how compelling one share may seem, any smart investor always stays diversified. Even the best companies can run into unexpected business challenges.

Chasing yield regardless of its source

A lot of ISA investors (and I include myself in this) like the passive income potential of a portfolio stuffed with dividend shares.

With a £20k portfolio, the current average FTSE 100 yield of 3.4% would mean annual passive income streams of £680. But a 5% yield would mean £1,000, while a 10% yield would mean £2,000.

The appeal of high yields is easy to understand. It can be addictive.

But as an investor, it is important always to remember that dividends are never guaranteed.

So instead of fixating on a share’s current yield, I try to look at its business prospects and assess what sort of yield I think it may be able to support in future.

Throwing good money after bad

I recently sold all my shares in Boohoo Group (LSE: DEBS). That was a painful decision to make, as not only did I sell for much less than I originally paid, but I also had to consider why I had squandered some of the money in my ISA to buy such a dog.

The reason was that, when I bought, Boohoo had proven its business model, had previously been profitable, was sitting on spare cash and had a strong brand and large user base.

Some of those potential strengths are still true and could help fuel a turnaround. But Boohoo has had an awful few years, losing money hand over fist while battling a downwards sales trend.

Finally I decided to cut my losses. But maybe I should have done that after my first purchase, rather than buying more shares when the price fell.

Badly chosen shares are not the only way one can waste money in an ISA: paying unnecessary fees and charges is another.

So, it pays to pick smartly when using a Stocks and Shares ISA to try to build wealth.

C Ruane has no position in any of the shares mentioned. The Motley Fool UK has recommended Apple. 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

Black woman using smartphone at home, watching stock charts.
Investing Articles

2 spectacular growth stocks to consider buying in March

Investors ignore the risks with growth stocks when things are going well. But when this changes, fixating on the dangers…

Read more »

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

Why is the FTSE 100 suddenly beating the S&P 500?

The UK's blue-chip index has been on fire over the past couple of years, helping it catch up to the…

Read more »

Artillery rocket system aimed to the sky and soldiers at sunset.
Investing Articles

This non-oil FTSE stock’s risen 4.6% in 3 days. What’s going on?

Against the backdrop of trouble in the Middle East, James Beard investigates why this FTSE 100 stock’s doing so well.…

Read more »

Three signposts pointing in different directions, with 'Buy' 'Sell' and 'Hold' on
Investing Articles

Has a 2026 stock market crash just come a whole lot closer?

If we're in for a stock market crash, what's the best way for us to prepare, and what kinds of…

Read more »

Silhouette of a bull standing on top of a landscape with the sun setting behind it
Investing Articles

Up 79% in a year, this FTSE 250 stock still gets a resounding Strong Buy from analysts

This under-the-radar growth stock in the FTSE 250 has been on fire over the past 12 months. Why are City…

Read more »

Frustrated young white male looking disconsolate while sat on his sofa holding a beer
Investing Articles

Vistry shares down 20%! Here’s what I’m doing…

Vistry shares have crashed as the firm cuts prices and moves away from share buybacks. But is Stephen Wright’s long-term…

Read more »

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

The IAG share price is climbing today despite war fears – what’s going on?

It's been a tough week for the IAG share price and Harvey Jones expects more volatility. Yet the FTSE 100…

Read more »

Businessman with tablet, waiting at the train station platform
Investing Articles

By March 2027, £1,000 invested in Natwest shares could turn into…

NatWest shares have been on a tear in recent years. What might the next 12 months have in store for…

Read more »