[drexlspivey]

BTC/Tether and BTC/USD are different trading pairs. If they printed a trillion tethers tomorrow and started buying bitcoins with them presumably people at some point would be unwilling to exchange BTC for tether. The BTC price might rise to 10 million tethers but the USD price would remain unaffected, effectively breaking the peg.

[millstone]

Presumably tether would trade at a discount to USD today, to reflect the non-zero probability that it is a scam.

[tim333]

This is true although Tether can maintain USD:USDT at one to some extent if either they have the dollars or if they have bitcoin and it's going up. They can then sell their bitcoin for dollars to buy the USDT. That falls apart if bitcoin drops.