The Long-Horizon Investing Principle
Time in the market beats timing: children's ISAs are the safest equity investment that exists
GoHenry made a deliberately counter-commercial decision to offer only a stocks-and-shares junior ISA rather than a cash version. The decision cost them inflows in the short term — cash ISAs are dramatically more popular with the British public — but it was driven by an evidence-based principle: for long-term investments, volatility is not the risk. Time horizon determines the risk profile, and a junior ISA held from birth to 18 has the longest possible runway for any retail financial product.
The British public's aversion to equities is a structural problem Hill traces directly to the absence of financial education. Only 6% of UK adults hold a stocks-and-shares ISA, compared to an estimated 50% of Americans who invest. That gap is not explained by income differences — it is explained by the absence of early financial education that normalises investing as something ordinary people do. The same mechanism that causes people to avoid investing — unfamiliarity, perceived complexity, association with wealth — is what GoHenry's junior ISA is designed to disrupt before it sets.
The product choice (a single diversified BlackRock fund, no active selection) reflects the same principle: keep it simple enough that families who have never invested will start. Once started, compound interest does the persuasion — parents see their children's fund grow and begin investing themselves.
- Time horizon determines risk: a locked 18-year investment in equities is safer than a one-year cash account in real terms.
- Volatility is not risk for long-horizon investors — missing compound growth is the real risk.
- Choice paralysis is the enemy of first-time investors: one good diversified fund beats the best actively-managed selection most people won't understand.
- The parent who invests for their child plants a seed that often grows back to the parent — the rub-off effect converts non-investing parents.
- Compound interest requires time above all else: starting at birth with small regular amounts beats large lump sums starting at 16.
- Choose stocks-and-shares over cash for all long-horizon children's accountsIf the investment is locked in for 10 or more years (as a junior ISA is until the child turns 18), the evidence overwhelmingly favours equities over cash. The risk of a market downturn is real on a 1-year horizon; it is negligible on an 18-year one. The risk of inflation eroding a cash account over 18 years is near-certain.Pro tipUse the actual numbers: £100/month into a cash account at 3% over 18 years = ~£28,500. Into a diversified equity fund averaging 7% = ~£43,000. The gap compounds.WarningNever make this argument for money that might be needed within 5 years — the time horizon changes the risk calculation entirely.
- Choose simplicity over sophistication in fund selectionFor first-time investors, a single globally diversified fund (such as a BlackRock world equity index fund) removes the decision paralysis that causes most people to procrastinate indefinitely. The goal is to start, not to optimise. A good simple fund started today beats the theoretically optimal portfolio started in three months.Pro tipReject themed or trending funds (AI, clean energy, female founders) for this purpose — they introduce active judgements that non-expert investors cannot sustain across 18 years.WarningFund managers selling thematic funds have incentive to move investors between funds — this realises capital gains and resets the compound clock. Resist.
- Set up automation and then ignore itAutomate the monthly contribution to the junior ISA or SIPP and then treat it as a sunk cost. Hill put child benefit into SIPPs for both children and 'forgot all about it' for years. The automation removes the temptation to liquidate in a downturn and allows compound interest to operate uninterrupted.Pro tipAlign the contribution amount with an income that already exists and isn't felt — child benefit, a regular bonus, the money you save from packed lunches vs restaurant meals.
- Show the child their balance and explain what it meansThe pedagogical value of a junior ISA is wasted if the child never sees it. Show them the balance quarterly, explain what stocks are, point to a market rise and fall and show them both happened and the balance is still higher than they put in. The account is a living lesson in compound interest, market volatility, and long-term thinking.Pro tipName what the fund could pay for at 18 — a car, a flat deposit, a gap year. Concrete future goals make abstract investing emotionally real for children.
When GoHenry launched the junior ISA, the market data showed cash ISAs are dramatically more popular with British consumers. Trading 212 tripled its business by adding a cash ISA. GoHenry chose to offer only stocks-and-shares, knowing it would result in fewer ISA accounts, because the evidence said it was right for the customer.
Hill set up SIPPs for both children when they were young, split the child benefit payment between the two accounts, automated the contributions, and then forgot about them. When her daughter turned 18, she received a letter from the SIPP provider asking her to notify Isabella that she had accumulated X pounds.
GoHenry's research shows that adults who had financial education as children are 40% more likely to be employed and 46% more likely to start a business. Hill extrapolates: 18 to 19 year olds alone, that equates to 123,000 new jobs, a 7% reduction in unemployment, and £6.98 billion additional GDP per year.
Hill chose stocks-and-shares over cash despite commercial pressure to offer both, based on the fundamental mismatch between British savings culture and optimal long-term financial outcomes. She frames it as a values-before-revenue decision: the customer's money comes first. She also practised what she preached — when her children were young, she put the child benefit payment into SIPPs for both of them and then 'forgot all about it', allowing compound interest to work uninterrupted until her daughter turned 18.