Rollover Financing is the interest paid or earned for holding a position overnight. Each day that your position remains open, we make a cash adjustment to your Account Balance to reflect the funding costs of your positions. The funding adjustment is based on the 'Tom-Next' spread of the currency pair involved.
Generally, the interest rate on the currency you bought is higher than the interest rate of the currency you sold, then you will earn interest (positive roll). If the interest rate on the currency you bought is lower than the interest rate on the currency you sold, then you will pay interest (negative roll).
The financing costs for all the currency pairs can be found here.
A credit or debit for each open position at GMT22:00 (GMT21:00 during US daylight saving hours)* will be applied directly to your Account Balance and will appear on your statement.
The Wednesday rollover also incorporates the weekend (so 3 days financing in total) which explains why you may see a fractionally higher financing cost/benefit in your trade report.
*Please note that the platform connection will be cut from 21:50 to 22:10 (from 20:50 to 21:10 during US daylight saving hours) for MetaTrader 4 and from 21:58 to 22:10 (from 20:58 to 21:10 during US daylight saving hours) for LION Trader due to the daily processing of the rollover.