When a position is carried over to the next business day, swap points (swap interest rates) are received or paid. Swap points will not be given out if a freshly opened position is closed on the same day without spanning a business day.
When the day's trade is over, swap points are given up in the evening at New York time. This is roughly 7:00 a.m. the next day in Japan time, and around 6:00 a.m. in the United States during daylight saving time. During this time, Forex businesses frequently halt trading and undertake maintenance in order to complete daily settlements and other tasks, and swap points are handed over (some Forex companies can trade even during maintenance).
When date and time processing is done, the swap point value is usually calculated and reflected in the account the next business day.