I just noticed that a few of the info cards for the various research techs are kind of vague.
A good example would be the pervasive economy tech, the info card says "Your income earns a fraction of the cost of all other empires expenditures, whenever purchases are made."

Ok that sounds pretty clear to me, but when you add that it has "Trade to credit conversion"
and "Sale to credit conversion" it muddies the waters somewhat (In my opinion) and makes it seem like it only applies to the black market.

Maybe I'm just stupid and cant read it correctly.