For the first time, Tether holders are actually redeeming Tether for actual $$$. Tether has fallen 9% in market cap over the last 4 days. $6.5 billion dollars have been pulled out in a controlled way, in fractions every 12-24 hours. The question is when Tether runs out of actual $$$. If it is after like ~$20 billion withdrawn, we are looking at losses of ~$50 billion. And it could take Bitcoin with it.
[edit] $8 billion down now.
People hold Tether to sell? Obviously this whole system is very stupid, the single-miner "coins" that central banks could issue to create digital cash that replaces traditional payment processors and other leeches on the financial system have utility. But these stablecoins are so stupid, they could work for their intended purpose of moving "value" between exchanges or whatever without using traditional banking/payment systems but without being prone to wild fluctuation in price. As anything someone holds for more than 10-20mins it takes to move money from one place to another they're very stupid.