Fractional dealing, the ability to buy part of a single share or fund rather than a whole unit, has been standard on consumer trading apps for years. It is now spreading into the layer underneath them: the white-label custody and dealing infrastructure that advisers, banks and wealth platforms resell rather than build. A tax rule that changed in late 2024 is a large part of why.
The most recent example is a contract renewal. WBS (formerly Winterflood Business Services), a UK provider of dealing, custody and technology to the investment industry, has extended its partnership with white-label savings platform Quai Digital for five years and added fractional dealing to the deal.
Quai Digital oversees around £4 billion across more than 520,000 accounts, including some 120,000 SIPPs, through its FCA-authorised subsidiary Quai Investment Services Limited.
On its own, that is a small deal between unevenly matched firms, with no commercial terms disclosed and no live date for the rollout. What makes it worth reading is that it isn’t the only one.
Why fractional dealing is spreading now
The blocker was tax, and it came down in November 2024.
In March 2023 HMRC took the position that fractional shares weren’t qualifying investments for a stocks and shares ISA. As law firm CMS put it, that stance “disrupted the market”: platforms could offer fractionals in a taxable account, but not in the tax wrapper most UK retail money actually sits in. For a provider trying to sell fractional dealing to the advised market, that made it close to unusable.
The 2024 ISA amendment regulations reversed it. The rules now allow “fractional interests in otherwise qualifying shares that are listed or traded on a recognised stock exchange (including listed or traded shares in funds) to be held in an ISA or CTF”, and came into force in November 2024. HMRC had spent the previous eighteen months signalling the change was coming; the regulations made it real.
That change is what matters here. Once a fractional holding can sit inside an ISA, a Junior ISA or a Lifetime ISA, the feature stops being a novelty for a general investment account and becomes something an adviser platform can put in front of ordinary savers. The infrastructure providers building it into their rails are responding to that, not to any single client win.
It is a category, not a one-off
Look across the intermediated market and the same capability keeps appearing, built once at the infrastructure layer and passed down to partner firms.
Seccl, a B2B-only custody and trading platform, offers fractional dealing to four decimal places and serves financial advisers, adviser-tech providers, neobanks and established fintechs. Its own description frames the point plainly: fractional trading “opens high-value stocks to every type of investor and portfolio” and lets partners “build diversified portfolios at lower minimum investments”.
WealthKernel, an API-first custody and dealing provider, offers fractional investing “from as little as £1” across general investment accounts, SIPPs and, on its roadmap, ISAs, and sells it to fintechs and wealth managers rather than to end investors. WBS already powers fractional share dealing for the advised platform Fundment, which added the capability for advisers in 2023.
None of this is brand new. Hubwise, now part of SS&C, launched fractional ETF units back in 2016. The shift worth marking isn’t the invention of fractional dealing in the wholesale channel, which is nearly a decade old, but the removal of the last regulatory reason not to scale it into mainstream advised and savings products.
It lowers the entry ticket, not the running cost
For the end investor, fractional dealing does one clear thing. It lowers the minimum trade. A saver with £50 can own a slice of a £300 share or a pricey index fund instead of being locked out of it entirely, and an adviser can run a model portfolio without rounding every client into whole units. That is a genuine widening of what a small pot can hold.
It doesn’t lower the cost of holding it. Platform fees, custody charges and adviser fees in this market are usually charged as a percentage of the value invested, and a percentage of a portfolio costs the same whether it holds whole shares or fractions of them.
The nominee administration behind a fractional holding is, if anything, slightly more involved. Fractional dealing changes the size of the ticket an investor can write. It leaves the running cost of the account where it was.
There is also a catch specific to fractions that whole-share investors never meet: fractional holdings are difficult to move. FINRA, the US regulator, states the position bluntly: “you can’t transfer fractional shares to another brokerage firm”, so an investor wanting to move “will have to sell them first, potentially incurring taxes and fees”.
Fractional owners may also lack the voting rights attached to a full share. Lock a client’s ISA into fractional holdings on one platform and the exit is a sale, with whatever tax that triggers, rather than a clean transfer.
That is the tension worth surfacing as this spreads. Building fractional dealing into the white-label layer genuinely widens access to the instruments a small investor can own. It does nothing for the fee structure that decides how much of their return those instruments keep, and it adds a portability problem they didn’t have before.
The open question
The regulation now allows it, and the rails are being laid across the intermediated market, provider by provider. What isn’t yet visible is whether the firms sitting on top of that infrastructure pass fractional dealing on in a way that reaches new, smaller investors, or simply bolt it onto accounts held by people who were already investing.
The Quai Digital deal is a fair test of that. WBS has built the capability; neither company has said when Quai’s partner firms will actually offer it, or what it will cost the saver at the end of the chain. Until that shows up in a real product, the access story remains a capability, not yet an outcome.
