Rollover rate is interest paid by a trader, who uses leverage, for keeping a position open for the next predetermined period of time. Since leverage implies the use of borrowed funds, these funds are not free. As a result, if a trader wishes to maintain a position open, some interest has to be paid to the provider of these funds.
It is important to know what’s considered a trading period as it may be different for each platform. Since a rollover fee is charged every trading period, how many hours a trading period represents directly affects the rollover costs. For example, CEX.IO Broker charges a rollover fee every four hours. So the rollover rate will be charged six times during a period of 24 hours.