Costs That Move With the Crowd: How Swing Pricing Quietly Reprices a UK Fund
Photo: Number 10, CC BY 2.0, via Wikimedia Commons
Most UK fund investors can quote the ongoing charge figure without reaching for a document. It appears on platform screens, in key information documents and in the annual charges summary, and it has become the default shorthand for what a fund costs. The difficulty is that the ongoing charge describes the cost of running the portfolio, not the cost of entering or leaving it. Those two things are related but not identical, and the gap between them is where dilution adjustments live.
The Cost That Is Not in the Ongoing Charge
When an investor buys units in an open-ended fund, the manager must put the new cash to work. When an investor sells, the manager must raise cash, often by selling holdings. Both actions incur dealing costs: commission, stamp duty where applicable, bid-offer spreads and, in less liquid markets, market impact. If those costs were absorbed by the fund itself, they would be spread across every remaining investor, including those who did nothing. Dilution is the process by which the value of existing units is eroded by the dealing activity of others.
UK authorised funds address this through dilution protections. The two common mechanisms are a dilution levy and swing pricing. A dilution levy is a separate charge applied to incoming or outgoing investors, paid into the fund to offset the expected dealing costs. Swing pricing adjusts the fund's dealing price itself, so that the price paid by an incoming investor is moved upwards and the price received by an outgoing investor is moved downwards when dealing activity crosses a defined threshold. In both cases, the aim is the same: to pass the cost of a dealing decision to the person who made it.
What Swing Pricing Looks Like in Practice
Swing pricing is not a penalty and it is not a performance fee. It is a pricing convention. Under a typical arrangement, the fund calculates a net flow figure each dealing day. If that figure exceeds a threshold set out in the prospectus, the price is adjusted by a factor intended to reflect the estimated cost of the resulting trades. Below the threshold, the fund may deal at its unadjusted net asset value, accepting that ordinary day-to-day flows are part of the cost of running a portfolio.
The threshold matters. A fund with a high threshold will swing only on unusually large flows, which means smaller investors are less likely to encounter the adjustment. A fund with a low threshold may swing more often, and the adjustment becomes a more regular feature of the dealing price. Neither approach is inherently better; they reflect different judgements about the size and behaviour of the investor base. What matters for an investor is knowing which regime applies and whether it is disclosed clearly.
The maximum swing factor is another point to check. Prospectuses typically state a cap, often expressed as a percentage of the dealing price. That cap is not a forecast of the adjustment; it is a limit. In ordinary conditions the applied factor should be smaller. But the cap gives a sense of the range the fund considers plausible, and a notably wide cap is worth understanding before committing capital.
Reading the Prospectus Without Reading Everything
A full prospectus is a long document, and most investors will not read it cover to cover. The dilution terms are nonetheless locatable. Look for the sections headed dilution, swing pricing, pricing and dealing, and fair value pricing. The key questions are straightforward. Does the fund operate a dilution levy, swing pricing, or both? What is the threshold, if one is published? What is the maximum adjustment? Who decides when it applies, and is the decision governed by a documented policy?
It is also worth checking whether the fund uses fair value pricing, which adjusts the value of holdings when a market is closed or disrupted. Fair value pricing and swing pricing are different tools, but they both affect the price at which units are dealt, and a fund that uses both should explain how they interact. A prospectus that is vague on these points is not necessarily a bad fund, but it is a fund whose dealing costs are harder to audit.
The Practical Audit
Begin with the platform. UK investment platforms are required to disclose costs, but the level of detail on dilution varies. Some show a dealing price and a mid price; others show only the price at which the deal will be executed. If the fund swings, the difference between the two can be material on the day of dealing, particularly for larger trades.
Next, compare the fund's dealing price with its published net asset value on a few dates. A persistent gap in one direction may reflect swing pricing, fair value adjustments or simply the timing of the valuation. It is not conclusive, but it is a prompt to read further. For investors dealing in size, or dealing regularly, this is a more useful exercise than comparing ongoing charges to two decimal places.
Finally, consider the strategy. Dilution adjustments are most consequential in funds that hold less liquid assets: small companies, emerging market equities, high-yield credit and property. In a large, liquid equity fund, the adjustment may be small and infrequent. In a fund that trades thinly, the cost of accommodating flows can be significant, and the dilution mechanism is doing more work. That is not a reason to avoid such funds, but it is a reason to understand the terms before dealing.
The ongoing charge remains a useful starting point. It is not, however, a complete account of what a fund costs an investor who buys and sells. Dilution protections exist because fund dealing has a price, and the question for any investor is who pays it. A few minutes with the prospectus, and a habit of checking the dealing price rather than the headline charge, will answer that question more reliably than any single figure on a platform screen.
