Turning a £20k ISA into second income of £17.5k a year

It’s possible to generate a hefty second income from a relatively small investment in FTSE 100 shares, provided we give it long enough.

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.

Young black colleagues high-fiving each other at work

Image source: Getty Images

The main reason I invest in stocks and shares is to generate a second income from company dividends to fund my retirement. I’m certainly not going to rely on the UK State Pension. Yes, it’s a reliable safety net, but depending entirely on it is a pathway to misery.

The Stocks and Shares ISA is a brilliant way to build that income, as everything I take will be free of tax.

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.

Someone who gets the new full state pension of £10,600 a year today, plus a further £20,000 from an ISA, would be earning north of £30,000 before paying a penny in income tax. That’s bad news for HMRC but good news for ISA investors.

Start planning young

I’ve set myself a target of generating £17,500 of income a year, from an initial investment of £20,000. I’m already beginning to regret that, because it sounds impossible. Yet success depends on how far off retirement is.

Let’s say I was 30 years old and invested this year’s full ISA contribution limit in FTSE 100 shares, and matched the long-term average total return on the index of 6.89% a year. Assuming a retirement age of 67, that £20k would have plenty of time to compound and grow.

After 37 years, it would have grown to £235,343. If the average yield on the shares in my portfolio was 7.5%, they would generate income of £17,650 a year. That’s a pretty good return on my original, relatively modest, sum of money.

This shows the power of long-term investing, especially in dividend stocks, as small initial sums can really roll up over the decades.

Yet there are obvious problems with my figures. It takes a good few decades to turn £20,000 into £235,000. An older investor almost certainly couldn’t do it unless they took outsized investment risks and they mostly paid off.

I’d buy shares like these

Another danger is that my shares could generate a lower return than 6.89% a year (although they might do better). Plus of course inflation will erode the value of that income in real terms.

Generating income of 7.5% a year may sound a tall order, yet in my defence, plenty of FTSE 100 stocks return that today. For example, housebuilder Barratt Developments yields 7.73% a year, while insurer Aviva yields 7.75% and British American Tobacco pays income of 8.18% a year.

At the higher end of the yield scale, Vodafone Group pays 9.66% a year and asset manager M&G returns a whopping 10.21%. So I think my portfolio target is doable.

Dividends aren’t guaranteed and can be cut or scrapped at any time. High yielders are particularly vulnerable. That’s why I would invest in a balanced portfolio of at least a dozen FTSE 100 stocks, so if some struggle, others will hopefully compensate.

Also, I wouldn’t stop at investing £20,000, regardless how young or old I was. I’d aim to use as much of my ISA allowance as I could afford every year, to generate the maximum possible dividend income and share price growth. By doing that, I would hope my second income is much higher than £17,650 a year by the time I retire.

Harvey Jones has positions in M&G Plc. The Motley Fool UK has recommended British American Tobacco P.l.c., M&G Plc, and Vodafone Group Public. 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

British flag, Big Ben, Houses of Parliament and British flag composition
Investing Articles

Back above 10,000! Is the FTSE 100 index on track again?

The FTSE 100 index has been yo-yoing up and down with the latest news headlines around the oil crisis. Where…

Read more »

Finger clicking a button marked 'Buy' on a keyboard
Investing Articles

Stock market correction: Is there still time to buy UK shares cheap?

Long-term investors can do well to stay calm through stock market corrections, and even crashes, and pick up shares when…

Read more »

Warm summer evening outside waterfront pubs and restaurants at the popular seaside resort town of Weymouth, Dorset.
Investing Articles

2 FTSE 100 blue-chips to consider for a new £20k Stocks and Shares ISA

Ben McPoland highlights a pair of high-quality FTSE 100 stocks that have strong momentum on their side yet are trading…

Read more »

Young Caucasian woman with pink her studying from her laptop screen
Investing Articles

Are depressed Lloyds shares just too tempting to miss now?

Lloyds shares are coming under renewed pressure as conflict in the Middle East threatens the fragile global economic recovery.

Read more »

Female student sitting at the steps and using laptop
Investing Articles

7 FTSE 100 shares that look cheap after the 2026 stock market correction

Falling stock markets often present bargain opportunities. Let's take a look at some of the cheapest FTSE 100 shares at…

Read more »

piggy bank, searching with binoculars
US Stock

Up 59% this year, this S&P 500 stock is smashing the index!

Jon Smith points out a stock from the S&P 500 that's flying right now as part of a transformation plan,…

Read more »

Businessman hand stacking money coins with virtual percentage icons
Investing Articles

Stock market correction: a rare second income opportunity?

Falling share prices are pushing dividend yields higher. That makes it a good time for investors looking for chances to…

Read more »

Finger clicking a button marked 'Buy' on a keyboard
Dividend Shares

I just discovered this REIT with a juicy 9% dividend yield

Jon Smith points out a REIT that just came on his radar due to the high yield, but comes with…

Read more »