No, you are not allowed to hold positions overnight or over the weekend. All trades must be closed before 20:30 UTC and between 20:30 UTC and 00:05 UTC (next day) there should be no trading activity. Similarly, all positions must be closed by 20:30 UTC on Fridays, and no new trades can be opened until 00:05 UTC on Monday. These rules are designed to mitigate risks associated with market gaps and increased volatility during off-hours.