The claim is clearly stated in the Kobeissi Letter X post and echoed by Benzinga. But neither retrieved source provides the original dataset or methodology needed to confirm that the top 0.001% figure is exactly 3500% since 1976, or to establish how 'wealth' and household groups were defined. Without a fetched primary source such as a Federal Reserve release, academic paper, or database table, the claim cannot be authoritatively validated from the evidence gathered in this run.