We have some exciting news to share! The Motley Fool UK has now become an independent, UK-owned company, led by our long-serving UK management team — Mark Rogers, Chris Nials and Heather Adlington. In practical terms, it’s the same team you know, now fully focused on serving our UK readers and members.

Just as importantly, our approach remains unchanged: long-term, jargon-free, and on your side. We’ll be introducing a new name and brand over the coming weeks — we're very excited to share it with you and embark on this new chapter together!

How I’d invest £20k in an ISA today

If Edward Sheldon was looking to invest £20k in an ISA right now, there are a few simple moves he’d make to target strong long-term returns.

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.

Middle-aged black male working at home desk

Image source: Getty Images

Investing within a Stocks and Shares or Lifetime ISA is one of the best ways to build wealth in the UK. Within these accounts, all gains and income generated are tax-free.

Here, I’m going to explain how I’d invest £20k in an ISA today. These are the moves I’d make in an effort to create long-term wealth.

Please note that tax treatment depends on the individual circumstances of each client and may be subject to change in future. The content in this article is provided for information purposes only. It is not intended to be, neither does it constitute, any form of tax advice. Readers are responsible for carrying out their own due diligence and for obtaining professional advice before making any investment decisions.

Spreading my risk

If I was putting money to work within an ISA today, one thing I’d certainly do is take a diversified approach to investing.

Diversification is the process of spreading money over many different investments (not putting all of your eggs in one basket). And it can significantly increase the chances of being a successful investor.

While shares tend to generate strong returns over the long term, not every stock is going to do well. For every JD Sports Fashion (up around 70% over the last five years) there’s a BT Group (down around 40% over the same period).

Ultimately, diversification reduces the risk of investing a lot of money in a dud. To diversify, I could buy a range of different stocks with my £20k. Alternatively, I could invest some of my money in funds or investment trusts for instant diversification.

A global approach

I’d also take a global approach to investing. The UK has some world-class companies. Diageo, Unilever, and London Stock Exchange Group are some good examples.

But let’s face it – a lot of the world’s most dominant companies (Apple, Amazon, Alphabet, etc) are listed overseas. And many of these internationally-listed companies are generating strong returns for investors.

Apple, for example, is up about 300% over the last five years.

So I’d spread my £20k across both UK and international shares.

It’s worth noting that buying US shares in an ISA is very easy today. One issue to be aware of however, is foreign exchange rates. If I was to buy a US-listed stock today, and the pound immediately strengthened against the US dollar, my holding would be worth less in GBP terms.

Small-cap stocks for big gains

Finally, I’d invest in both large-cap stocks and small-cap shares.

Investing in large caps has plenty of benefits. Larger companies often pay dividends and their share prices tend to be more stable than small-caps.

But for big gains, it’s hard to beat small-caps. Often, smaller companies are growing at a spectacular rate. Meanwhile, they tend to be less researched, meaning there’s more potential for better-than-expected results and explosive share price movements.

An example of a UK small-cap that has done really well in recent years is Cerillion. Five years ago, it was trading at around 150p. Today however, it’s near 1,300p, meaning a £2k investment has grown into more than £17,000.

Taking a long-term approach

Of course, making these three moves wouldn’t guarantee success. But I reckon that over the long term, this approach to investing £20k should work pretty well.

Ed Sheldon has positions in Alphabet, Amazon.com, Apple, London Stock Exchange Group, Cerillion Plc, Diageo Plc, and Unilever Plc. The Motley Fool UK has recommended Alphabet, Amazon.com, Apple, Cerillion Plc, Diageo Plc, and Unilever Plc. Suzanne Frey, an executive at Alphabet, is a member of The Motley Fool’s board of directors. John Mackey, former CEO of Whole Foods Market, an Amazon subsidiary, is a member of The Motley Fool’s board of directors. 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

Young mixed-race woman jumping for joy in a park with confetti falling around her
Investing Articles

Here’s how someone could aim for a million with a handful of shares!

Are you a gambler or an investor when it comes to trying to find realistic ways to aim for a…

Read more »

Hand flipping wooden cubes for change wording" Panic" to " Calm".
Investing Articles

Things are getting tough for this FTSE 100 share. But I’m not selling!

This FTSE 100 share has fallen 17% in value since the beginning of the year. Royston Wild thinks this may…

Read more »

pensive bearded business man sitting on chair looking out of the window
Investing Articles

Here’s how much passive income £5k invested this month could earn in years to come

Christopher Ruane explains how someone with a few thousands pounds to invest could seek to build passive income streams, thanks…

Read more »

Young female business analyst looking at a graph chart while working from home
Investing Articles

Could buying Microsoft stock now be like buying Alphabet in mid-2025 at a share price of $150?

Microsoft’s share price has fallen in 2026 as investors moved away from software names. But Edward Sheldon sees potential for…

Read more »

Asian man looking concerned while studying paperwork at his desk in an office
Investing Articles

A £3.8bn warning for Legal & General shareholders

Legal & General shares currently offer one of the highest dividend yields in the FTSE 100 index. The big question…

Read more »

Man hanging in the balance over a log at seaside in Scotland
Investing Articles

Down 61% and a P/E of 5.9! Is this FTSE 100 share FINALLY rebounding?

JD Sports has been one of the FTSE 100's worst performing shares of the last five years. But latest results…

Read more »

UK supporters with flag
Investing Articles

How to build a £20,000-a-year passive income from a Stocks and Shares ISA

Andrew Mackie looks at high-conviction stock ideas he believes could help investors build long-term wealth in a Stocks and Shares…

Read more »

Young happy white woman loading groceries into the back of her car
Investing Articles

With a P/E of 15.4, my Tesco shares no longer look cheap. Are there better options out there?

Tesco shares have hit a high and no longer look like the reliable, defensive name they’ve long upheld. But don’t…

Read more »