"What would be the negatives with sharing information with each other? " In general in the dark world of secret services, there is a "need to know" principle,

"What would be the negatives with sharing information with each other? " In general in the dark world of secret services, there is a "need to know" principle, about protecting sources. Meaning, what someone does not know, he cannot leak. Because when the enemy knows, that file X leaked and he knows that only 5 persons had access to that file, they can find the source easily. That has been happened a lot of times accidently, but likely has even been used to activly sabotage each others operations, as the bosses of each others service did not liked each other to put mildly. https://en.m.wikipedia.org/wiki/Wedge:_The_Secret_War_Between_the_FBI_and_CIA https://en.m.wikipedia.org/wiki/Wedge:_The_Secret_War_Betwee...