The situation with tether is much much worse. About 30% of the money invested in tether is gone and unlikly to come back. The books do not balance, it is not a timing issue, it isn't a liquity issue tether or bitfinex is insolvent.
This is important to realize, tether or bitfinex is insolvent/bankrupt if that 850m is truly gone. It is covering up this with loans between related parties, but the legality of those loans is probably questionable at best but bitfinex and tether are intertwined such that they likely have shared liabilities legally.
Someone is bankrupt right now. Maybe both.
The fact that tether or bitfinex isn't dropping or outright dead confuses the hell out of me. Is it so critical to crypto now and so central that even if it is involvement we have to believe in it or the sake of this whole market? This market isn't rational or I must be missing something.
Also, unattended arbitrage bots might end up equalizing the price now but becoming major bag-holders later. Right now, the spread between the Coinbase & Bitfinex BTC prices is > $300. The logical response of an arbitrage bot is to buy Bitcoin on Coinbase (spending USD) and sell it on Bitfinex (receiving USDT); they provide the Bitcoin liquidity that people who want out of Tether need. This creates a counterflow of BTC from Coinbase to Bitfinex, spending down their dollar reserves at Coinbase and accumulating a Tether hoard at Bitfinex. If the bottom falls out of Tether, their accumulated profits (and any capital invested) becomes worthless.