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How to turn a £20k ISA into a second income of £10k a year!

Buying dividend stocks in an ISA can be a good way to earn a second income. Here’s how our writer would invest a £20k portfolio in pursuit of that goal.

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I use a Stocks and Shares ISA to fulfil many of my investing needs. With a generous £20k annual contribution limit and no taxes on capital gains or dividends, using an ISA can be a great way to buy stocks and earn a second income.

Imagine I wanted to aim for a passive income stream of £10,000 a year from one year of maximum ISA contributions. How would I approach this objective? And how long would it take to earn a five-figure dividend haul?

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Buying dividend stocks

It’s important to distinguish between income-generating shares and stocks that don’t pay dividends. Since earning passive income is my priority, many popular companies wouldn’t be suitable investments because they don’t issue regular distributions. So, that rules out the likes of Amazon, Meta, and Tesla.

This leads me to wonder which stocks I should consider buying

Fortunately for investors seeking exposure to UK shares, almost all FTSE 100 businesses provide shareholders with cash payouts. Companies in Britain’s leading index generate the vast majority of their aggregated income from overseas. However, I’d also consider buying US dividend stocks for additional portfolio diversification, as well as shares from other international markets.

Currently, my stock market positions span a variety of firms in different sectors. I focus on several metrics when investing for a second income, such as the stock’s dividend yield, dividend cover, and the company’s dividend history. Examples of dividend shares I own include:

Dividend stockForecast yieldForecast cover
British American Tobacco 9.5%1.6x
GSK3.9%2.6x
Johnson & Johnson3.0%2.1x
McDonald’s2.4%1.9x
Rio Tinto 6.8%1.7x

Earning a second income

To accelerate my journey towards earning £10k in annual passive income, I’d reinvest my dividends within a Stocks and Shares ISA. Not only is this tax-efficient, but pursuing this strategy allows me to benefit from the power of compound returns over time.

If I secured a 5% yield across my stocks, I’d need a portfolio worth around £200k. In essence, my ISA would need to increase tenfold in value. That’s no mean feat, but I can factor share price appreciation into the equation too.

The compound annual growth rate (CAGR) of my combined holdings would dictate how long this would take. To illustrate this, here’s what my journey to a five-figure dividend income could look like at different rates of return.

Portfolio CAGRTime taken
5%47 years, 3 months
7.5%31 years, 11 months
10%24 years, 2 months
12.5%19 years, 7 months

No guarantees

Turning a £20k ISA into an income generator that would yield 50% of my original investment takes time and demands patience. But, aided by some smart stock picks, I could potentially achieve this goal in less than two decades!

That said, my modelled scenarios assume a positive return. Over long time periods, volatility arguably becomes less of a concern. Even so, there’s a risk my stocks could underperform and deliver a negative return.

In addition, dividends aren’t guaranteed. So, if my portfolio’s yield dropped, I might need a larger investment pot to generate £10k in payouts.

Accordingly, although stock market investing can be a great way to earn a second income, investors should remain alive to the risks involved.

Randi Zuckerberg, a former director of market development and spokeswoman for Facebook and sister to Meta Platforms CEO Mark Zuckerberg, 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. Charlie Carman has positions in Amazon.com, British American Tobacco P.l.c., GSK, Johnson & Johnson, McDonald's, and Rio Tinto. The Motley Fool UK has recommended Amazon.com, British American Tobacco P.l.c., GSK, Meta Platforms, and Tesla. 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.

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