有趣。 根据下面的文字,用spot price当benchmark是不合适的,应该用near month future price。 This is quoted from UNG website: The investment objective of UNG is for the changes in percentage terms of the units' net asset value to reflect the changes in percentage terms of the price of natural gas delivered at the Henry Hub, Louisiana, as measured by the changes in the price of the futures contract on natural gas traded on the New York Mercantile Exchange that is the near month contract to expire, except when the near month contract is within two weeks of expiration, in which case it will be measured by the futures contract that is the next month contract to expire, less UNG's expenses.