10% a day is astronomical!.Making 10% consistently on every trading day on almost all 200 trading days in a year would result multiplying your starting trading capital by a factor of 189 million! Itâs simply impossible to sustain such growth because markets are small and wealth gain is finite. As your trading position grows in size the harder it becomes to get filled at a good price, let alone you would soon reach your brokerage firmâs trading size limit.