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Investors can aim for a £1,000 monthly second income starting with a £20k ISA

With the ISA deadline fast approaching, Zaven Boyrazian explores how investors can aim to earn a £12,000 second income in the stock market.

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With uncertainty in the British economy still elevated, investors earning a passive second income have a significant advantage over most individuals.

Earning extra cash without having to lift a finger is key to achieving financial freedom. And with the ISA deadline fast approaching, now could be the perfect time to start leveraging the wealth-building power of the stock market.

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As with all investments, there are risks to consider. And nothing is ever guaranteed. But given enough time, it’s possible to transform a £20k Stocks and Shares ISA into a £12,000 annual income stream – the equivalent of an extra £1,000 a month.

Earning £12k a year

Following the 4% withdrawal rule, investors aiming to earn an extra grand each month will need an ISA valued at around £300,000. That’s obviously not pocket change. But when starting with £20k already in the bank, it’s a goal that’s far more achievable than most might think.

Even with a passive strategy of investing in a FTSE 100 index tracker, a £20k ISA could reach the £300k threshold within just under 34 years, even without injecting any more capital. This estimate assumes that the UK’s flagship index continues to deliver its historical 8% annual average return moving forward. And while 34 years is a long time to wait, the process can be drastically accelerated by throwing in small regular monthly contributions.

For example, adding an extra £150 each month to the portfolio would slice almost nine years off the waiting time. And for those able to inject £500 every month, the timeline shortens to just 17 years.

Seeking extra returns

Not everyone has the luxury of having spare cash at the end of each month for investments. Fortunately, there’s another way to speed up the wealth-building process – stock picking. This strategy is far more hands-on and requires a higher degree of risk tolerance. However, by picking individual stocks, it’s possible to achieve returns that outpace the FTSE 100’s 8%.

Take BAE Systems (LSE:BA.) as an example to consider. Over the last five years, the aerospace and defence enterprise has seen its valuation fly by over 160% as defence spending ramped up as a result of the Ukraine and Gaza conflicts. On an annualised basis, that’s the equivalent of a 21% return. If this rate of return were to be maintained, the timeline to transform £20k into £300k and unlock a £12k second income would be just 13 years, even without adding any extra capital.

Taking a step back

As exciting as this prospect sounds, earning a 21% annualised return for 13 years straight is far from easy. Even someone as skilled as Warren Buffett has only managed 19.9%.

Meanwhile, BAE’s recent success is currently being primarily driven by short-term tailwinds in defence spending across Europe. However, that could change should the ongoing conflicts come to a peaceful resolution. Don’t forget after the Iraq war ended in 2011, BAE’s growth slowed considerably until geopolitical tensions started to rise again in 2022.

All of this is to say that while BAE appears to have market-beating traits today, that may not always be the case. After all, it’s a cyclical business. And it’s entirely possible for a hand-crafted portfolio to underperform the FTSE 100 if constructed or managed poorly.

Zaven Boyrazian has no position in any of the shares mentioned. The Motley Fool UK has recommended BAE Systems. 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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