Best for Large Pots
Flat-fee SIPP from Interactive Investor. Fixed monthly charge rather than percentage — excellent value for larger pension pots.
Interactive Investor charges a flat monthly subscription rather than a percentage, which makes it unusual among UK pension platforms and increasingly cheap as a pot grows.
The arithmetic is straightforward: a fixed fee on a large balance is a small percentage, while on a small balance it is a large one.
Who it suits. Investors with substantial pension pots, where the flat fee works out well below percentage-based competitors. The crossover point is typically somewhere in the tens of thousands.
Worth knowing. On smaller pots the flat fee is genuinely expensive relative to percentage-charging rivals. Work out your own crossover before switching, and remember that the pot will grow — the right answer at £20,000 may be wrong at £150,000.