Investment platforms are preparing for new ISA rules as cash interest rates start to disappear

Investment platforms are starting to stop paying interest on uninvested cash ahead of the changes to ISA rules from April 2027.

Chancellor Rachel Reeves used her 2025 Autumn Budget to reveal new restrictions on cash ISAs in an attempt to encourage more people to invest rather than keeping their money in cash.

From April 2027, under-65s will only be able to put up to £12,000 into a cash ISA each tax year, down from the current £20,000 that can be used across the tax wrapper. They will still have the overall £20,000 annual ISA allowance, so if they put £12,000 into a cash ISA, the remaining £8,000 could go into a stocks and shares ISA.

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Transfers from stocks and shares ISAs to cash ISAs will also be banned as part of the changes.

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Plus, HMRC has said it will introduce a charge for those earning interest on cash within a stocks and shares ISA.

The aim is to disincentivise investors from keeping cash holdings in a stocks and shares ISA for a long time and instead encourage them to put the money back into the market.

For now, many of the major investment platforms are still paying interest on uninvested cash.

But J.P Morgan Personal Investing appears to be getting its investors ready for the changes now.

Cash pot changes

It may be tempting to keep money in cash while you decide where to invest, especially if you are earning some interest.

But the Treasury wants to get more people investing, ideally in UK stocks, so the new charge aims to provide a disincentive as it could outweigh any interest earned.

J.P Morgan Personal Investing is going a step further by removing the interest paid on cash-only pots.

Currently, the robo-wealth manager pays the Bank of England base rate minus 2.5% on its cash-only pots.

This is money that investors can use to drip-feed funds into their portfolio or to protect your balance from market movements ahead of a withdrawal.

It is separate to cash held in the investment pot that goes towards management fees. Interest on this cash is currently paid at the base rate minus 0.75%.

But from 22 June, J.P Morgan said cash-only pots will no longer accrue interest.

Instead, cash‑only pots will remain available for holding cash and drip feeding money.

Any interest accrued up to but not including 22 June 2026 will be paid into your pot at the end of the current quarter.

Interest will still be paid on cash held in your investment pot.

Can you still earn interest on uninvested cash in a stocks and shares ISA?

HMRC is due to consult on the changes and other investment platforms are still paying interest on cash for now.

BestInvest pays a relatively decent 2.98% interest on cash holdings within any of your investment accounts.

In contrast, AJ Bell’s stocks and shares ISAs, lifetime ISAs, and junior ISAs pay 1.75% interest on all cash balances.

The interest paid can also depend on the amount being held.

For ISAs and junior ISAs, interactive investor now pays 1.11% on the first £20,000, 1.26% on the value between £20,000 and £50,000, 1.36% between £50,000 and £100,000, and 2.21% on the value above £100,000.

Hargreaves Lansdown users can earn 1.51% on cash balances between £0 and £19,999, 1.18% between £20,000 and £99,999, 2.02% between £100,000 and £999,999, and 2.38% on balances worth £1 million and higher.

MoneyWeek has asked the major platforms what there plans are once a charge is introduced.