What are your overnight financing charges?

• Equities, Indices, Commodities: 
Total Position Size x 3.5% / 365 – Let’s take Barclays as an example. 
Total Position size (exposure) - £10000 x 3.5% (Libor + 3) = £350 / 365 = 95p per day in Financing. Please note that for a weekend roll the charge is only applied once but the underlying market spread will be bigger as you are rolling a position for 3 days as opposed to just one. 
FX: 
The interest calculation is based on the currencies involved in the trade you have open. The ETX charge is based and calculated on the underlying exchange rate at 20:00 hrs, both are then applied to the size of position(s) you have running and overnight interest is either debited or credited as a ledger entry on your a/c on a daily basis on any open positions held. 

The overnight funding is derived from the funding charges paid to maintain an open position in the underlying interbank foreign exchange markets often referred to as the Tom/next (tomorrow/next day borrowing, 'swap' or 'swap points') i.e. it is a tradeable market in swaps that moves with interest rate expectations and supply and demand in a similar way to the spot market moves although short dated swaps are traded at the front end of the curve and are very small spreads/”pips” usually to 5 and 6 decimal places
Also, please note that the underlying market swap rates change and are not fixed so charges may vary and will change when the factors that are used to derive them change, whereas the ETX charge is fixed at 0.0054 % and is competitive when compared to other market participants. Overnight Financing can be accrued or charged depending on the direction of the trade and the intrument that is being traded.