Fraud does not automatically make it a Ponzi, and no custodial service will have sufficient USD on-hand at all times to cover everyone withdrawing their funds.

The specific claim that was made by GP, and the claim that I see bandied around, is that Tether is a Ponzi scheme.

Tether doesn't appear to share any characteristics with a Ponzi scheme, which is why I am puzzled to see people so adament it is one.

The most important characteristic (IMO) is that there is no promise of a return. $100 of Tether will only ever be worth $100 maximum.

If anthing, Tether is basically operating as an unregulated bank. You're not calling banks Ponzis are you?