Over the course of the past week, Tether has redeemed a significant amount of USDT from the circulating supply of tokens. In line with this, Tether will destroy 500m USDT from the Tether treasury wallet and will leave the remaining USDT (approx 466m) in the wallet as a preparatory measures for future USDT issuances.
Conceptually, the Tether issuance and redemption process is outlined in the Tether White Paper, with issuances and redemptions visible through observing the Tether treasury balance on the OMNI blockchain.
For more information, please refer to Tether.to.