5 last-minute ISA mistakes to avoid

ISA deadline time is almost upon us and it pays to use up your allowance, but be careful not to make these common mistakes.

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 only got a couple of weeks left now before the 5 April deadline for using up your 2017-18 ISA allowance. But be careful, and don’t fall into these common traps.

Not making the most of it

With a tax-free allowance of £20,000, it seems almost criminal to me to not make the maximum use of it that you can. I know very few people can afford to invest the full £20,000, but even a small amount missed today could mean a significant loss by the time you retire.

If you invest £1,000 today and achieve a 6% annual return, in 30 years you’ll have £5,700. And if you match the 30-year historical record of the FTSE All Share index of around 8% per year, you’ll nearly double that to £10,000 for every £1,000 invested.

Buying a Cash ISA

I see a Stocks & Shares ISA as a great idea, but think a Cash ISA is a dead duck. Sadly, millions of people in the UK put money into a cash ISA every year and get interest rates of a just a couple of percent per year at best.

It can be far more profitable investing in something that performs better and even to pay tax on the profits, than to save the tax on a lousy investment. Click here to learn more about the way shares have beaten cash hands-down over the long term.

Buying the wrong thing

I’ve covered the importance of using up as much of your allowance as you can, but I want to add a caution — it’s better to not invest in anything than invest in the wrong thing.

So don’t frantically look for shares to buy before the deadline and end up picking stocks that you might not buy if not under time pressure. I would never buy a stock unless I was confident I understood it and I was fully convinced of its long-term prospects, ISA or no ISA. The upside of not paying tax is nowhere near enough to compensate for the risk of buying something I hadn’t researched.

Fortunately, you don’t have to actually buy the shares by 5 April, you just need to get your money in by then.

Taking money out

Cashing in some of your ISA investments for short-term things, like a better holiday or a more extravagant birthday bash than you could otherwise afford, is forfeiting the beneficial effects of long-term investing.

There’s not a lot of point saving just a year or two’s tax on a short-term investment, when those savings could multiply massively over the long term and provide you with a significantly bigger tax-free pension pot.

Remember from above, if you take out £1,000 now, you could knock £10,000 off your retirement fund.

And you can’t put it back once you’ve filled your allowance — invest £20,000, take out £2,000, and you can’t top up beyond the remaining £18,000 again.

Forgetting your children

If the long-term benefits of investing in a Stocks & Shares ISA are that good, just think how much better they’ll be for your children now that we have the Junior ISA.

Introduced in 2011, the Junior ISA currently has an annual limit of £4,128 per year. I’ve written about the Junior ISA in more depth here. But £4,128 invested from birth with a 6% annual return would be worth £132,000 by age 18, and would grow to £1.5m by age 60 with nothing extra added.

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 »