Necurs, the world’s largest spam botnet, is sending millions of spam emails that push an obscure cryptocurrency named Swisscoin. Such spam emails are known as pump-and-dump, and the technique relies on sending large quantities of spam to drive interest up towards a particular penny stock. Swisscoin, an altcoin described as a Multi-Level-Marketing (MLM) ponzi scheme) last year, lost 40% of its initial trading price since the Necurs spam started spreading.
Source: https://www.bleepingcomputer.com/news/cryptocurrency/worlds-largest-spam-botnet-is-pumping-and-dumping-an-obscure-cryptocurrency/