Costs & FeesStart here

The only component of a return that is known in advance, guaranteed to occur, and compounds against you.

Why costs deserve their own chapter

• Returns are uncertain, volatile and unknowable in advance. Costs are certain, stable and knowable — which makes them the one input an investor genuinely controls.
• They compound. A 1.5% annual drag is not "1.5% less" after thirty years; it is roughly a third of the terminal wealth, because the fee is charged on the balance the fee has already shrunk.
• They hide in at least six places, and product literature discloses them at six different levels of enthusiasm.

The six layers

• Ongoing charges (TER / OCF) — management fee plus administration, accrued daily out of NAV. Never billed, always paid. The headline number, and the only one most investors see.
• Transaction costs inside the fund — the fund's own trading spreads and commissions. Not in the TER. High-turnover strategies can add 0.2–1% p.a. that never appears in the ongoing charge.
• The bid-ask spread you pay — on entry and again on exit. On a liquid ETF, a couple of basis points; on a thin bond or a small-cap, a percent or more per side.
• Tracking difference — for index products, the actual gap between fund and index return. Sometimes better than the TER implies, when securities lending or tax treatment works in the fund's favour; often worse.
• Platform, custody and FX — the broker's own layer. Currency conversion on a foreign-listed holding is frequently the largest single fee a retail investor pays and the least itemised.
• Performance fees — the alternatives layer. See the fee drag and waterfall calculators for what 2-and-20 compounds into.

Trading costs: the part that scales with activity

• Half the quoted spread is the implicit cost of an immediate fill — you buy at the offer and mark at the mid, so the loss is booked the instant you trade. See market microstructure for where the spread comes from.
• Market impact is the extra cost of being large: your own order moves the price against you. Impact grows roughly with the square root of order size relative to daily volume.
• Slippage is the gap between the price you decided at and the price you got — impact plus drift while you waited.
• Everything above is per round trip and multiplied by turnover. A strategy that turns over four times a year pays it eight times.

How costs are disclosed — and where the gaps are

• Ongoing charges figures are standardised in most retail regimes and genuinely comparable between funds of the same type. Use them; just do not assume they are complete.
• Transaction costs inside the fund are disclosed under some regimes and estimated under methods that can produce negative numbers. Treat as indicative.
• Structured products embed their margin in the terms, not in a fee line: a cap that is slightly too low or a coupon slightly too small is a cost you can only see by pricing the components yourself. The option pricer and the strategy builder exist partly for this.
• FX conversion is usually quoted as a spread to an unnamed reference rate. Compare the rate you received to the interbank mid at the time — the difference is the fee.
• Taxes are jurisdiction-specific and out of scope here. They interact with turnover in the same direction as costs: activity is expensive.

Practitioner rules

• Add every layer before comparing anything. A cheap fund on an expensive platform can cost more than the reverse.
• Convert costs into the return they demand. Every basis point of cost is a basis point of skill the strategy must produce just to draw level.
• Costs are the most reliable predictor in the fund literature — more stable than past performance, which is the one thing marketing leads with.
• Turnover is a cost decision disguised as an investment decision. Before trading, ask whether the expected improvement exceeds the round trip.
• Do not chase the last basis point into illiquidity. A product two basis points cheaper with a spread five times wider is more expensive for anyone who ever sells.

Tracking difference: the cost number that is actually measured

The ongoing charge is what a fund says it costs. Tracking difference is what it actually delivered against its index — the only cost measure that captures everything at once, including the parts nobody discloses.