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How to invest £20,000 in an ISA to get passive income for life

Here’s how investors can aim to transform £20,000 a year into a quality seven-figure ISA portfolio that generates a £43,000 tax-free, lifelong, passive income.

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The annual ISA allowance grants UK investors the opportunity to build a passive income from investments almost entirely tax-free.

While stamp duty’s still charged on some transactions, all capital gains and dividends can be enjoyed without HMRC knocking at the door. And in today’s era of higher taxation and rapidly rising prices, making the most of the £20,000 allowance is critical when striving for financial freedom.

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So let’s break down exactly how a new investor can start unlocking a new lifelong income.

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.

Setting expectations

Everyone loves the idea of getting rich quick. But in the stock market, wealth takes both time and discipline to build. The most reliable and successful wealth-building strategy is a long-term one, investing in quality and letting compounding work its magic.

That means even with £20,000 to invest on day-one, the initial passive income likely won’t be life-changing. In fact, following the 4% rule, it would likely only sustainably generate £800 a year.

But when left to compound at the stock market’s 8% long-term average return for 20 years, every £20,000 transforms into just shy of £100,000, or £98,536.06 to be precise. That’s five times the original amount invested, significantly outpacing inflation and unlocking a chunkier £3,941 lifetime passive income in the process.

What if someone continues to make use of their £20,000 ISA allowance each and every year? After two decades, the same portfolio would now be worth £1,080,433 – enough to generate a £43,217 sustainable income. And thanks to the ISA wrapper, both the seven-figure portfolio and the five-figure passive income can be enjoyed entirely free from tax.

Finding quality opportunities

Not everyone has the luxury of putting aside £20,000 for their ISA each year. However, even with a few hundred pounds to spare each month, becoming an ISA millionaire remains entirely within reach for investors who start as early as possible.

But the question now becomes, which quality stocks should I buy? When looking at the top picks from the analyst team at Peel Hunt, Mortgage Advice Bureau (LSE:MAB1) currently stands out as a top candidate.

At a share price target of 1,250p, the mortgage brokerage network provider could be about to climb as much as 120% if Peel Hunt’s right. And to be fair, the bull case is quite compelling.

With millions of pandemic-era fixed-rate mortgages about to switch to variables rates, there’s an enormous pipeline of remortgaging about to take place to re-fix rates. And since this business earns advisory and commission fees, this massive volume opens the door to an incoming revenue surge.

Does that make this a no-brainer? Maybe. But like all investments, there are risks to consider. Even if the top line goes through the roof, the bottom line is a bit more complex.

Mortgage Advice Bureau doesn’t exist in a vacuum. And with other mortgage referral businesses looking to cash in on this opportunity, the company could be forced to cut its fees to remain competitive. In other words, margins could be squeezed, preventing the stock from reaching Peel Hunt’s lofty target.

Nevertheless, as a toll-booth to the UK mortgage market, the company’s highly cash generative – exactly the sort of business that can turn into a long-term quality compounder. That’s why I think investors should take a closer look.

Zaven Boyrazian 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.

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