Why This Stuff Costs $2700 Trillion Per Gram - Antimatter at CERN

I have a vague recollection of some hypothesized difference in behaviour between particle/anti-particle pairs at the event horizon of black holes (resulting in Hawking Radiation) as possibly holding some hint to the relative absence of anti-matter in the observable universe.
But I don't have a sufficient basis in the relevant physics, or sufficiently detailed memory of this maybe-hypothesis, to perform the searches necessary to so much as confirm or deny my recollection of this as an actual-hypothesis, let alone one grounded in viable theory.