A fee cap changes the shape of a charge not its direction

Some providers apply a percentage charge up to a maximum annual amount. The cap is presented as a benefit, and understanding who it benefits requires looking at where it binds.

What a cap actually does

A percentage charge grows without limit as a portfolio grows. A cap converts it into a fixed amount above a certain balance, so the charge stops rising beyond that point.

Below the cap nothing changes. The charge behaves exactly as an uncapped percentage would, and the cap has no effect on the amount paid.

The cap therefore benefits only those whose balances exceed the crossover point. For everyone else it is a feature of the pricing that never becomes relevant.

The effective rate falls as the balance rises

Once the cap binds, the charge expressed as a proportion of assets declines with every additional pound held. A large portfolio pays a smaller effective rate than a medium one.

This is the opposite of how the uncapped structure behaves, where the effective rate is constant. The cap introduces a discount that arrives entirely at the top.

Whether that is reasonable depends on the underlying cost of service, which does not obviously scale with portfolio size. The cap is arguably a correction rather than a concession.

Caps are often narrower than they appear

Many caps apply only to certain asset types. A cap on exchange-traded holdings does not limit the charge on funds held in the same account.

Caps may also apply per account rather than per customer, so splitting assets across account types can mean the cap is approached separately in each.

Dealing charges and other fees usually sit outside the cap entirely. The capped element is one component of the total rather than a limit on what the provider can charge.

Comparing capped and flat structures

A capped percentage and a flat fee converge at high balances. Below the crossover the percentage is cheaper, and above it the two structures charge similar amounts.

The crossover point is the only figure that matters in the comparison, and it can be calculated from the published rate and cap in a few seconds.

Most people never perform that calculation and select on the headline rate instead, which is the number that describes the part of the structure they will actually pay.

Caps change what a portfolio can afford to hold

Where a cap binds, adding assets to the same account costs nothing further in that charge. That alters the arithmetic of consolidation for larger holdings.

It also removes the charge as a reason to keep a portfolio small, which is relevant for anyone weighing whether to hold additional assets in the same place.

Charging structures are revised regularly and caps are among the first elements to move. A structure chosen on a cap is worth rechecking at the annual review rather than assumed permanent.