WordNet records no synonym and no antonym for insider trading. 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.
buying or selling corporate stock by a corporate officer or other insider on the basis of information that has not been made public and is supposed to remain confidential
Synonyms, antonyms and the broader and narrower relations for insider trading come from Princeton University’s WordNet. Full sources and licences.