It can be both.  No information usually means no trade however it can also be confidential data.

Is there a list which national entities are reporting data to comtrade? I used to think German data was reported by Destatis (Germany's national statistics department) and was wondering why 2006 data wasn't appearing in comtrade until a few days ago, when we actually had trade data from Destatis available since early spring. However, after ...

There are two different aspects in this question: International merchadise trade statistics is concerned with goods physically crossing the border and it does not matter who buys and sell. For example if the UN buys food in Malaysia which is used for emergency aid and shipped to another country then Malaysia would record an export to this ...