"It's clear that Tether was the kickstarter to the mania by printing about 2 billion in 2017 on a total market of 1 - 10 billion in the last 10 years."
https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3195066
This means it was likely manipulation/speculative buying since the theory behind fair value states price and fv should match once all speculation is gone.
