How to turn £120K Traitors’ prize money into £2.1m

Imagine being driven away victorious from the Traitors’ castle in the Scottish Highlands with the £120,000 prize pot in your hands. No more Missions or dark glamour from the fantastically fringed Claudia Winkleman, and an end to lying and treachery (maybe).

Bar any pressing short-term needs, the winner might splash out on holidays, or perhaps exercise some restraint and save it. How many prizewinners would prove to be a 100% Investing Faithfuls though and put it all into the stock market?

• Invest with ii: SIPP Account | Stocks & Shares ISA | See all Investment Accounts

Hard data demonstrates that this is the shrewdest move, as despite the inevitable bad years for shares, history tells us that investing over the long term outstrips inflation and returns on cash savings, meaning greater wealth. Despite the evidence, there are still plenty of Britons holding long-term savings in cash. In the words of Winkleman, “what are they not seeing” about the value of investing?

So, while no one can predict what future returns from the stock market will be, our calculations reveal how investing the Traitors’ prize pot of £120,000 over 10 years could see it more than quadruple in size, leaving the winner with more than £500,000.

Let’s gather at the investing round table for some number crunching…

In the round: the numbers

BlackRock, the world’s largest asset manager, has just published a list of average annual returns for different asset classes over the past 10 years, and an annualised return of 14.5% for US equities looks pretty exceptional.

According to consultancy firm McKinsey, the S&P 500 has delivered annualised total returns of a still impressive 9% over 25 years (1996 to 2022), but we’re using BlackRock’s figures to generate potential returns for all assets over the next 10 years. However, it's worth reminding readers that these are historic returns, and markets may not replicate this boom period for stock markets and many other assets over the next decade. 

Why 10 years? Well, investing is very much a long-term game since the stock market is vulnerable to periods of volatility, and leaving your money to compound (where investment returns generate their own returns) for 10 years, means there’s plenty of time for it to grow.

So, according to our calculations, if you invested the £120,000 prize pot in US equities for 10 years, it could potentially grow to more than four times the original sum, hitting £507,147. That’s quite a nest egg for a little delayed gratification.

In comparison, £120,000 kept in cash for the next 10 years would see it grow by only £29,499, reaching a total of £149,499.

Compounding in plain sight

Source: BlackRock Asset Return Map. Annual index total returns (income or dividends reinvested) in US dollars. *Total returns data from Morningstar and in GBP. Calculations assume annualised returns remain consistent for the next 10 years. Past performance is not a guide to future performance. Costs have not been taken into consideration.

Keep more of the Traitors’ money with this tax shield

If you opt to keep your £120,000 Traitors’ prize in savings accounts, you’d pay income tax on your interest. If you are a basic-rate taxpayer (paying 20% income tax), you have a personal savings allowance of £1,000, meaning you can earn £1,000 of interest before paying any tax on it. For higher-rate taxpayers (40% income tax), the sum falls to £500. So, if your Traitors’ winnings are in savings accounts, you’re going to lose a big chunk to the taxman. Ouch.

ISAs, whether cash or the stocks & shares version, would keep the taxman’s hands off your windfall, but each adult only has a £20,000 annual allowance, meaning you’d still need an alternative home for a big chunk of your winnings.

However, providing you can manage without the money until your late 50s, you could invest it in a self-invested personal pension (SIPP). Current rules allow you to access a SIPP at 55, rising to 57 in 2028. Investments in a SIPP are sheltered from tax as they grow, just like an ISA. With a SIPP, you have the freedom to choose your own investments, and you can open one alongside a workplace pension.

• Investment outlook: expert opinion, analysis and ideas
• Key tax changes impacting investors in 2026

You can pay the lower of £60,000 or 100% of earnings a year into a pension, but then there’s carry forward rules to potentially take advantage of too. These allow you to utilise any unused pension allowance from the previous three tax years. So, depending on your level of pension contributions over the past few years, you could potentially shovel the remaining £60,000 into your SIPP too. In addition, pension contributions attract upfront tax relief at the individual’s marginal rate, so your winnings would get an additional boost.

If you did put the money into a pension, depending on your age, it’s possible that the money would be invested for much longer than 10 years.

Here’s the projected returns across different assets classes over 20 years:

Source: BlackRock Asset Return Map. Annual index total returns (income or dividends reinvested) in US dollars. *Total returns data from Morningstar and in GBP. Calculations assume annualised returns remain consistent for the next 20 years. Past performance is not a guide to future performance. Costs have not been taken into consideration.

Banish the cash account?

The point of all this Traitors’ fantasizing has been to illustrate the value of investing over keeping your money in cash savings. However, it’s not about completely banishing cash. Sometimes, keeping money in cash makes sense, for instance as an emergency fund - typically three to six months’ salary - to cover problems such as broken white goods.

While the sum in this piece happens to be £120,000, you don’t need such a large amount - or anything like it - to start investing.

If you’re new to investing or perhaps haven’t started yet, you may fear losing hard-won savings, so-called loss aversion. But there are sources of information to help you:

• What to invest in when getting started: a beginner’s guide
• How to invest a lump sum

But, even when global markets fell to their lowest point during the Covid pandemic in March 2020, I didn’t lose all my money (possibly the ultimate fear for those still in cash), and by November, my investment (in a diversified low-cost fund) had recovered.

This year, it’ll be seven years since I started investing. I’m now a dyed-in-the-wool Investing Faithful.