WordNet records no synonym and no antonym for pyramiding. It is the only member of its synset, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a fraudulent business practice involving some form of pyramid scheme e.g., the chain of distribution is artificially expanded by an excessive number of distributors selling to other distributors at progressively higher wholesale prices until retail prices are unnecessarily inflated
Synonyms, antonyms and the broader and narrower relations for pyramiding come from Princeton University’s WordNet. Full sources and licences.