Share your opinion and earn yourself a free Motley Fool premium report!

We are looking for Fools to join a 75 minute online independent market research forum on 15th / 16th December.

To find out more and express your interest please click here

How much income could a £20k ISA generate in a year?

An ISA is my number one choice for building up a growing long-term income pot. And the early rewards can be just the beginning.

| 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.

Passive income text with pin graph chart on business table

Image source: Getty Images

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.

The idea of putting an entire year’s Stock and Shares ISA contribution limit into a single investment would scare me. Unless, that is, I’d already built up a large and diversified portfolio and the £20k wouldn’t be a large proportion of it.

Even then, if I had to pick just one, it might have to be something like City of London Investment Trust (LSE: CTY). Yet while it’s a diversified investment trust, it still has its risks. It is, after all, a company in itself with a single management team.

And if it failed to raise its dividend one year, I reckon the share price could tumble.

Long-term dividends

Dividend rises are especially key here, as this trust has increased its annual cash payout every year for the past 58 years. Seeing that falter could be painful.

But the diversification makes this as close to a ‘buy-and-forget’ stock as I can think of. It’s effectively the same as buying a collection of shares in HSBC Holdings, Shell, BAE Systems… and all the other top-drawer UK stocks it holds for income generation.

And with a forecast dividend yield of 4.5%, I’d say it’s a good one to use to try to answer my headline question. So how much could I earn from it?

On the face of it the calculation seems straightforward. If I pony up my £20k and get a 4.5% dividend yield, I’d earn £900 in income in a year. But that’s just the start of the story.

The years ahead

I don’t actually want to take any income from my ISA at the moment. Instead, I let my dividend cash build up until I have enough for another share purchase… and back in it goes.

In the first year I’d have that £900 to reinvest. But if I bought more of the same, in the second year I’d get £940.50. The extra £40.50 would be the 4.5% dividend I’d get from the extra £900. And then in year three I’d earn £982.82. And so on, with each year’s dividend payment getting bigger and bigger.

By the time I reach 10 years, my initial £20k could have grown to £31,060. And that’s without investing a further penny over the decade. Stick with it for another decade, and my pot could reach £48,230.

Compounding magic

The first 10 years could make me a profit of £11,060. But the second 10 years could add another £17,170. And that’s why many investors see compounding as their best friend. This example shows how later years can make more money than early years, and reinforces the importance of investing for the long term.

Oh, I haven’t considered any share price gains here. In reality, I’d expect the annual dividend to rise and the share price to go along with it and keep the yield roughly stable. And that could give my long-term hopes a further boost. Not that any of this is guaranteed however.

But I reckon a stock like this is a good one to consider for investors starting their first ISA… though perhaps not with their full allowance.

HSBC Holdings is an advertising partner of Motley Fool Money. Alan Oscroft has positions in City Of London Investment Trust Plc. The Motley Fool UK has recommended BAE Systems and HSBC Holdings. 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

Investing Articles

3 FTSE 100 predictions for 2026

2025 has been a blockbuster year for the FTSE 100. Here’s what Edward Sheldon thinks will happen with the stock…

Read more »

Young woman holding up three fingers
Investing Articles

Want to start investing in 2026? 3 things to get ready now!

Before someone is ready to start investing in the stock market, our writer reckons it could well be worth them…

Read more »

Investing Articles

Can the stock market continue its strong performance into 2026?

Will the stock market power ahead next year -- or could its recent strong run come crashing down? Christopher Ruane…

Read more »

Businessman hand stacking money coins with virtual percentage icons
Investing Articles

Here’s how someone could invest £20k in an ISA to target a 7% dividend yield in 2026

Is 7% a realistic target dividend yield for a Stocks and Shares ISA? Christopher Ruane reckons that it could be.…

Read more »

A quiet morning and an empty Victoria Street in Edinburgh's historic Old Town.
Investing Articles

How little is £1k invested in Greggs shares in January worth now?

Just how much value have Greggs shares lost this year -- and why has our writer been putting his money…

Read more »

Businessman using pen drawing line for increasing arrow from 2024 to 2025
Investing Articles

This cheap FTSE 100 stock outperformed Barclays, IAG, and Games Workshop shares in 2025 but no one’s talking about it

This FTSE stock has delivered fantastic gains in 2025, outperforming a lot of more popular shares. Yet going into 2026,…

Read more »

Close-up of British bank notes
Investing Articles

100 Lloyds shares cost £55 in January. Here’s what they’re worth now!

How well have Lloyds shares done in 2025? Very well is the answer, as our writer explains. But they still…

Read more »

Thoughtful man using his phone while riding on a train and looking through the window
Investing Articles

How much do you need in an ISA to target £2,000 a month of passive income

Our writer explores a passive income strategy that involves the most boring FTSE 100 share. But when it comes to…

Read more »