Funding cost by broker
Sorted cheapest to most expensive. Rates are SONIA + broker markup, applied to the full notional value.
How charges accumulate
Cheapest (IG) vs most expensive (Saxo).
Funding is charged on the full notional value, not just your margin deposit. A position requiring only £4,000 margin could have a notional value of £80,000 — and the funding charge applies to the full £80,000. This is why overnight funding can significantly erode profits on longer-term positions.
How overnight funding works
Every spread bet you hold past the end-of-day cut-off (typically 10pm UK time) incurs an overnight funding charge. This is the cost of the leverage your broker extends to you — you only deposit a fraction of the position's full value as margin, and you pay interest on the rest.
For GBP positions, funding is typically calculated as SONIA + a broker markup, applied to the full notional value of your position and divided by 365 for a daily rate. A tighter markup compounds into real savings on positions held for weeks or months.
Why broker choice matters
On a £40,000 notional position held for a year, a 0.5% difference in funding rate is £200 — straight off your bottom line. For position traders and swing traders who hold for days or weeks, funding can quietly become one of the largest costs of trading.