What to do when you fill your S&S ISA in the UK in 2026?
According to FT Adviser 2.5 million were able to fill their ISAs (both cash and stocks and shares) in the tax year to April 2023. So What do you do when you have filled your ISA?
Pre-requisites
Lets assume those able to fill their ISAs and realise the tax free allowances are savvy enough to have the pre-requisites sorted. But just in case good financial management basics are to have a cash buffer as an emergency fund - depending on your risk appetite between 3-12 months expenses. Some people might choose 3 months of critical expenditure - the mortgage, council tax, food, electric and gas as everything else can be cancelled. Some might choose 3 months of total expenditure, including all the bells and whistles. Some choose longer if they feel like their job is a risk, or they know they are running an older car that is making odd noises. You do you.
The thing with cash is that it gets eaten by inflation. So it’s best to find the highest savings rate possible, to offset inflation as much as possible. Inflation is the cost of convenience of having the money easily available, so making it last as long as possible makes sense. Due check every 6 months to a year on whether it still is enough for you. Council tax saw a 5% rise this year, remortgaging might mean a jump in mortgage payments that you are able to pay month-to-month but if something was to cause you to dip into your emergency fund to find that 3 months of costs is only 5 weeks you might be in trouble.
Next up is your pension. It’s still the best retirement investment tool. The employer match, the tax relief is all free money, so perhaps more going into your pension is worth considering. Note that there is a carry-forward allowance, but a tapered allowance for high earners (earning £260k). So do check. The limit is on relevant earnings or £60k - whatever is lower.
The Options
That all said and done, lets look at the options once the ISA is filled.
Premium Bonds
First up is Premium Bonds, there is a limit of £50k per person, so giving money to the spouse, if applicable, means a household could see £100k. It’s also protected by NS&I so as safe as money can be. Assuming average luck you might win tax free prizes1 from the monthly prize draws up to £1m.
There is no guaranteed savings rate1, but it’s a good protected place to hold cash, perhaps this forms part of your retirement strategy to avoid selling out of the market during a down turn.
Spouse’s ISA
Next is the spouse’s ISA. That’s another £20k allowance per year that could be growing tax free. Even if your partner is a spending not a saver, you can agree to use the allowance rather than lose it.
Kids JISA
A good option for your kids is to open a JISA, there are some platforms that have no fees - in the hope they’ll stay a customer during adulthood - but these come in cash and S&S variants. Given the child can only access the funds at 18 and the money is legally theirs - so bear this in mind - it can be worth investing and accepting the short term volatility for higher growth. It’s also possible for grandparents to pay some money in - which might be more welcome than another piece of plastic.
There is a £9k annual limit and one JISA per child. Once the money is in, it is theirs and locked away until they are 18. Could be great for a first house deposit, a car, or uni fees.
Kids JSIPP
Now to go even more long term, there is the kids junior SIPP or JSIPP. This comes with a gross limit of £3,600, i.e. with tax relief at the basic rate added on. It’s locked away until 57 currently, but due to change in 2028. But just £5k lump sum in a JSIPP for a 5 year old, assuming average 5% real growth per year, would be worth just over £75k in today’s money by age 60.
Contribute £250 a month, and have them continue in adulthood when it becomes their regular SIPP it could be worth a staggering £950k at 60 in today’s money.
GIA
And then, the general investment account. There is no tax wrapper protection here, but just capital gains (£3k) and dividend (£500) allowances which have been cut over the last few years.
If you have the wealth this makes a lot of sense and unlike the spouse’s ISA, Kid’s accounts, the money is still yours.
VCT / EIS
Higher-rate and additional-rate taxpayers often consider these after maxing their pension and ISA, largely for the 30% income tax relief - there is a minimum 5 year holding period. But venture capital trusts and enterprise investment schemes - which has CGT deferral and loss relief - are both high risk. They typically invest in unlisted companies often in a group, say 10 or so, in the intention or acceptance is that many will fail, but some will launch and get further seed funding etc and an exit. Definitely one for a financial advisor if you are at this level of income/risk tolerance.
Offsetting/overpaying mortgage
Frequently overlooked as an “investment,” but for many people a guaranteed mortgage-rate return beats GIA on a risk-adjusted basis. You effectively get the guaranteed return of your mortgage rate and in August 2026 that could be around 4.8 to 5%. It’s likely a worse return than the stock market over the long term especially considering inflation, but there is certainty, low risk, and it is good for the mind and heart knowing that your expenditure can drop by what is likely the largest outgoing each month.
Alternative Options
LISA
A LISA is a type of ISA, so if you are already filling your £20k allowance this is no good, but it’s worth considering in certain circumstances by contributing the maximum £4k here, then only £16k can go in your regular ISA.
Again LISAs like ISAs and JISAs come in cash or stocks and shares variety. The key benefit is the government top up 25% of contribution up to £1k per year. However, you must open one before you are 40, you’ll face a penalty for withdrawing early, you can only contribute up to the age of 50, and withdraw from age 60 (albeit tax free) unless you are using the fund to purchase a house. The house also needs to be under £450k and be your first home.
As of August 2026 there is a review of the LISA so details may change and new products maybe available to help first time buyers.
Solar and Heat Pumps
This is probably the most underused item on the list, but capital outlay on solar panels, battery storage, and heat pumps might be a big saving long term. It is not likely to outpace the stock market, but preparing for retirement and reducing your costs in later life can be effective. It’s possible to reduce your energy bills to zero or even better, make some money if you can generate enough and sell it back to the grid using appropriate SEG (smart export guarantee) tariffs.
Check with installers and your energy supplier for details to see if your home can support this setup - i.e., home is energy efficient, has insulation, double glazing, and of course any building regulations and planning permission that may be needed.
And still money to spend
Then consider increasing your charitable giving, salary sacrifice schemes, and increasing your discretionary spending.
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Note: Premium bonds values can change see NS&I for more details and latest prizes ↩ ↩2
