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

£20k in a Stocks & Shares ISA? Consider targeting a £3,121 monthly passive income like this

Looking to build a large passive income for retirement? Royston Wild show how a diversified ISA portfolio could build long-term wealth.

| 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.

Close-up image depicting a woman in her 70s taking British bank notes from her colourful leather wallet.

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.

With a lump sum investment, investors could start a journey with a Stocks and Shares ISA that might eventually see them become totally financially independent.

Personally speaking, I don’t want to take a chance with my retirement by relying on the State Pension. The size of the benefit I receive, along with the age at which I can draw upon it, is increasingly uncertain as the UK struggles to fund its fast-growing elderly population.

So I have a plan to build long-term wealth. It’s a strategy that, for investors with a £20,000 lump sum today, could potentially provide a monthly passive income above £3,000.

Ta-ta, taxman

The first step I’ve taken is to invest in a tax-efficient product like a Stocks and Shares ISA. This way, I’ve managed to keep any capital gains and dividend interest I receive out of the hands of the taxman.

Over decades of investing, this can add up to tens of thousands of pounds, perhaps more.

Asset manager Netwealth recently told the Financial Times that an additional rate taxpayer investing £100,000 in a Stocks and Shares ISA would, based on an average annual return of 5.9% over 10 years, save a whopping £44,000 in taxes.

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.

A big passive income

The next thing I’ve done is build a diversified portfolio of shares, funds and trusts with my ISA. I own around 10-15 companies that span a multitude of sectors and regions. I’ve also sought out a combination of value, dividend, and growth stocks.

By spreading my investment like this, I’m boosting my chances of achieving steady, long-term portfolio growth while balancing potential risks.

With this strategy, I believe an average annual return of 8.5% is a realistic and achievable goal. This figure sits at the midpoint between the FTSE 100‘s historical long-term average return of around 7%, and the S&P 500‘s higher average return of approximately 10%.

Past performance is no guarantee of future profits. But investors who can achieve that 8.5% return would — with a £20k investment, and an additional £300 top-up each month — have a Stocks and Shares ISA worth £749,061 after 30 years.

They could then enjoy a healthy monthly income of £3,121 a month by switching this into 5%-yielding dividend stocks. This is the next stage of my own investing plan.

A top trust

A simple and cost-effective way to hit this goal could be by considering an investment in a trust. Alliance Witan (LSE:ALW) — which is about to be promoted to the FTSE 100 from the FTSE 250 — is one such pooled investment I’m thinking about today.

This is one of the UK’s largest investment trusts following the recent merger of Alliance Trust and Witan Investment Trust. It has total assets of around £5.5bn, and holds shares in more than 230 companies.

These shares are spread far and wide, by industry as well as region, as shown below. This helps investors to manage risk, as well as obtain exposure to a wide variety of investment opportunities.

Portfolio by region
Source: Alliance Witan
Portfolio by sector
Source: Alliance Witan

On the downside, the trust has significant exposure to cyclical sectors like technology, industrials and financials. This can result in disappointing performance during economic downturns.

But over the long term, I’m optimistic it can continue delivering a healthy return. It’s why it’s near the top of my ISA shopping list today.

Royston Wild has no position in any of the shares mentioned. The Motley Fool UK has no position in any of the shares mentioned. 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

This way, That way, The other way - pointing in different directions
Investing Articles

Is the unloved Aston Martin share price about to do a Rolls-Royce?

The Aston Martin share price has inflicted a world of pain on Harvey Jones, but he isn't giving up hope…

Read more »

Surprised Black girl holding teddy bear toy on Christmas
Investing Articles

How much do you need in a Stocks and Shares ISA to raise 1.7 children?

After discovering the cost of raising a child, James Beard explains why he thinks a Stocks and Shares ISA is…

Read more »

smiling couple holding champagne glasses and looking at camera at home with christmas tree
Investing Articles

A Santa rally could take the FTSE 100 to 10,000 and beyond!

If the FTSE 100 enjoys yet another big Santa rally then the long-awaited and tantalisingly close 10,000 mark could be…

Read more »

UK coloured flags waving above large crowd on a stadium sport match.
Investing Articles

2 investment trusts from the FTSE 250 worth digging into for passive income

Plenty of FTSE 250 investment trusts offer dividend growth potential over the long run. So why does this writer like…

Read more »

Warhammer World gathering
Investing Articles

The Games Workshop share price is up 38% in a year. Is there any value left?

The Games Workshop share price has risen by more than a third in a year. Our writer considers what might…

Read more »

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

This AI growth stock could rise 60%-70%, according to Wall Street analysts

This growth stock has lagged the market in 2025. However, Wall Street analysts expect it to play catch up next…

Read more »

Surprised Black girl holding teddy bear toy on Christmas
Investing Articles

Prediction: here’s where the red-hot Lloyds share price and dividend yield could be next Christmas

Harvey Jones has done brilliantly out of the Lloyd share price over the last year. Now he's wondering whether he'll…

Read more »

Female Tesco employee holding produce crate
Investing Articles

Up 23% in 2025, are Tesco shares still capable of providing attractive returns?

Tesco shares have produced two to three years’ worth of investment returns in just 11 months. Can they continue to…

Read more »