Plenty of UK investors end up with their stocks and shares ISA scattered across two or three platforms — a Vanguard account opened in 2019, an old Hargreaves Lansdown one from a workplace nudge, maybe a Trading 212 pot started during a quiet weekend. Each one charges its own fees, sends its own statements, and quietly drags on the time you'd rather not spend on admin. Consolidating them onto one platform is one of those jobs that sits on the to-do list for years. Done properly, it can save you real money. Done carelessly, it can cost you your entire ISA allowance.
The rule that catches people out
Here is the single most important thing to understand: never withdraw the cash and re-deposit it yourself. The moment money leaves an ISA wrapper into your bank account, it loses its tax-free status. Pay it back in and it counts against this year's £20,000 allowance all over again. If you've got £60,000 spread across old ISAs and you withdraw the lot to "move" it, you cannot simply pour it back — you'd be £40,000 over the annual limit.
The correct route is an ISA transfer, handled platform-to-platform. You fill in a transfer form with the receiving provider, they contact your old provider, and the money moves while staying inside the wrapper the whole time. Your allowance is untouched. Crucially, this applies to ISAs from previous tax years with no limit — you can transfer £200,000 of old ISA money if you've got it, and none of it eats into this year's £20,000.
In specie versus cash transfer
You'll be offered two ways to do it. A cash transfer sells everything, moves the money, and you rebuy at the other end. An in specie transfer moves your actual holdings — your Vanguard FTSE Global All Cap units arrive at the new platform still as units, never sold.
In specie is usually the better choice because you stay invested throughout. With a cash transfer you're out of the market for the days or weeks the move takes, and if the market jumps 3% in that window you've simply missed it. The downside: in specie transfers are slower, sometimes painfully so — six to eight weeks is not unusual, and the occasional horror story stretches past three months. They also only work if the receiving platform actually offers the same funds. Move a niche investment trust to a platform that doesn't stock it and you'll be forced into a cash transfer anyway.
Watch the exit fees
Some of the older platforms still charge to leave. Interactive Investor and a few others have historically levied per-holding exit fees, though the picture keeps shifting as platforms scrap them to win business. Before you start, ring the platform you're leaving and ask two blunt questions: what will you charge me to transfer out, and how long will it take? Get the answer in writing if you can. A £40,000 transfer that triggers £300 of exit fees might still be worth it if the new platform's annual charge is lower — but you want to know the number before, not after.
Is it actually worth the hassle?
For a percentage-fee platform like Hargreaves Lansdown, charging 0.45% a year on funds, a £50,000 ISA costs you £225 annually. Move that to a flat-fee platform such as Interactive Investor at around £156 a year, or a low-cost option like Vanguard at 0.15% (£75 on the same balance), and the saving compounds year after year. On a six-figure portfolio the gap between a percentage fee and a flat fee can run into four figures annually.
That said — and this is where the spreadsheet logic meets reality — consolidation isn't automatically right for everyone. If your money is genuinely small, the percentage platforms are often cheaper than the flat-fee ones, because £156 a year on a £10,000 pot is a punishing 1.56%. The flat-fee platforms only win once your balance is large enough for the maths to flip, usually somewhere north of £30,000–£40,000.
A sensible order of play
If you've decided to go ahead, a few practical steps keep it clean:
- Pick the receiving platform first, and check it actually holds every fund and trust you own.
- Request in specie transfers where possible to stay invested.
- Transfer one account at a time rather than all at once — easier to track if something stalls.
- Keep paying into whichever account you've nominated for this year's contributions, so you don't accidentally open a second ISA of the same type in one tax year, which the rules now permit but the platforms don't always handle gracefully.
None of this is fast and none of it is exciting. But a portfolio sitting on one platform, on a fee structure that suits its size, is the kind of boring housekeeping that quietly adds up over a couple of decades. Get the transfer form, not the withdrawal button — that's the whole game.