Dividends are corporate earnings that companies pass on to their shareholders. The payment of dividends has an impact on the price of the underlying asset.
When dividends are paid out to the shareholders the price of the underlying asset is reduced to keep the value of the asset unchanged.
When a specific share which is part of an Index is paying dividend, then the price of the Index is also affected by the percentage that this specific share is contributing to the index.
As CFDs replicate stocks, the dividend would be paid out (long position) or deducted (short position) to compensate for the difference in price that a dividend involves.
Dividends are only for Cash instruments, not for Futures.
The calculation for dividends is as follows:
Number of Contracts * Dividend Rate (Gross Amount) * Conversion Rate (to account currency)