> I'm pretty sure if they had damning evidence, a single hedge fund could single-handedly force the market to collapse in a couple weeks.
How would you do that? If you knew that Tether had, say, only $10 billion of assets backing it, you'd need to get 10 billion USDT and demand conversion to USD. If you bought those tether, well, it now has $20 billion of assets thanks to you and you lose. Borrowing seems risky, because the people you're borrowing from likely have a vested interest in Tether not collapsing and are going to work against you. So the only safe option is to convince people who hold 10 billion of USDT to cash out for USD pronto.
I will point out that the current drawdown of Tether is consistent with the scenario where liquid fiat assets are fast disappearing from the cryptocurrency ecosystems, and the cryptocurrency companies are fighting among themselves to claim as much of those assets as they can. (NB: There are likely other scenarios that are consistent with available evidence).