ISAs are one of the most popular ways to save and invest tax-efficiently in the UK — but the fees a provider charges can significantly affect your returns over time. Rather than freeze a list of provider prices (which change often), here’s how the fee models work, so you can compare whatever the current rates are.
The types of fee to look for
- Platform / account fee — for using the provider; a flat fee or a percentage of what you hold.
- Fund charges (OCF) — the ongoing cost of any funds you invest in, charged by the fund itself, separate from the platform.
- Trading / dealing fees — for buying or selling shares and ETFs (fund dealing is often free).
- Exit or transfer fees — for moving your ISA to another provider.
Two layers of cost
The point many people miss is that platform fees and fund charges are separate, and you pay both. A cheap platform holding expensive actively-managed funds can cost more overall than a slightly pricier platform holding low-cost index funds. To compare fairly, add the platform charge and the fund OCF together to get your real all-in cost.
Percentage vs flat fee
As with pensions, percentage-based platform fees tend to be cheaper for smaller pots, while flat-fee platforms can be much cheaper once your ISA grows into the tens or hundreds of thousands. Some percentage platforms cap the charge on shares and ETFs, which helps larger holdings. Work out the annual cost at your expected balance under each model.
Using fees to choose well
- Add up all the fees — platform, fund OCF and likely trading costs — for the real total.
- Match the fee model to how you invest: buy-and-hold investors should focus on platform and fund costs; frequent traders on dealing fees.
- Check each provider’s current published charges rather than relying on an old table.
- Read the small print for caps, inactivity charges and exit fees.
Understanding the fee models — and comparing today’s rates against your own situation — can make a real difference to long-term returns. Weigh total cost alongside investment choice, usability and service. This is general information, not a recommendation of any particular provider.