There are more than 5,000 Stocks and Shares ISA millionaires in the UK. And if we want to know how to join them… well, a look round the well-known ISA providers finds plenty of headlines telling us how.

Use the full allowance, never take any money out, buy the best stocks, reinvest all our income… blah-di-blah… I’m not going to trot all that out again. (Well, it makes sense, but we’ve heard it all before.)

Let’s be honest, most of us aren’t going to become millionaires. And I’m here to tell you that’s fine… all the millionaire blather is completely missing the point.

The other 99.9%

UK investors contributed to 4.1m Stocks and Shares ISAs in the 2023-24 year. And only slightly more than 0.1% of those, at most, could have a million in their account.

But a Stocks and Shares ISA isn’t a million-or-bust thing, and it’s not about hitting the ranks of the super-rich. At least, not for the other 99.9% of us. No, for us it’s about making our retirement as comfortable as we can, by investing a reasonable amount of our income.

We want to do better than we would without an ISA. And I reckon almost all of us should be able to achieve that — and it would be tax-free.

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.

Reality, please

The average 2025 annual UK salary, after tax, was around £30,000. And we’re being urged to max out our annual ISA limit, when very few of us can come close?

What about investing a tenth of the average income, or £3,000 per year? The FTSE 100 has returned an annual average of 6.9% over the past 20 years. At that rate, we could end up with £126,000 in our ISA in 20 years. Or £288,000 if we keep going for 30 years. And that’s not to be sniffed at.

Future returns might not be the same. But the UK stock market has more than a century-long record of beating other investments. One straightforward way to get in is with an index tracker like the iShares Core FTSE 100 UCITS ETF (LSE: ISF)… big name, simple thing.

Buy the biggest

The tracker aims to replicate the performance of the whole index. It’s like buying shares in AstraZeneca, HSBC Holdings, Shell… and all the other big ones. We can do it with just one single investment, and with very low charges the fund comes very close to its FTSE 100 target.

It’s also an investment that, for me, provides the most important thing for Stocks and Shares ISA newcomers. That’s not finding the flashiest get-rick-quick hopes. No, it’s providing diversification. Billionaire investor Warren Buffett’s famous Rule No 1: Never lose money.

Moving on

Buying this tracker does mean we’re not going to beat the market. And we’d suffer from any market-wide falls. So maybe then think about more focused investment trusts, and individual company shares after that.

But yes, we could achieve a lot with an ISA, without getting all starry-eyed about millionaire dreams.