I think so too however it looks like they may have printed their (counterfeited) way into solvency.
Basically: buy cheap BTCs, print shitload of tethers, sell BTCs for real USD to the tune of tens of billions and now store these real USD in short term US treasuries (they don't own chinese treasuries anymore) bringing in 5% and more.
They're claiming they now have excess money (!) to back their tether due to the fact that they collect 5% or more of interest on the short-term treasuries they have.
Put it this way: even if they printed $40bn out of their arses out of $80bn of tether, the $40bn of actual USD they'd have would still net them $2bn a year in interest. That'd still be a big hole but...
What if they printed "only" 10 bn out of thin air out of 80 bn: they'd have near 70 bn bringing in 3.5 bn yearly at the moment.
They don't give any of the interest back to USDT (tether) holders.
So if they printed "only" 10 bn out of their arses, in less than three years they'd have these 10 bn for real on interest alone.
It's still criminal (I guess) but it may not be "0% of tether are backed".
People have tried to run the maths on how much money entered the cryptocurrency world (with Coinbase giving a huge hint).
Centre (Circle+Coinbase) has really $24 bn backing their USDC coin (they publish the individual US short term treasuries bill number).
USDT (tether) is much older than USDC.
Did they cheat? Most certainly.
Did they "fake it 'till they made it", helped, by sheer luck, by interest rates going like crazy?
I think it's possible.