That's the whole point of a peg. If your thing goes below the pegged value, use your other assets to buy until your thing reaches pegged value (and vice versa). That's what "backed" means.
Circle have $1 which you can redeem each USDC for.
They don't theoretically have extra cash lying around to buy USDC at discount, and they certainly can't use reserves for that (they are needed to serve withdrawals)
Hopefully they do have some corporate cash spare to buy up cheap USDC so that what they lose to SVB doesn't make them insolvent
I fail to see the difference, note that the title mentions "depegs". If they buy 1 USDC at $0.9 with their reserves, they can remove the USDC, and keep $0.1 since they'll need $1 less reserve. How is this fundamentally different from a peg? This is exactly why nations with pegged currencies keep foreign cash reserves.
Backed only implies that the stablecoin creator can redeem 1-1. It doesn't imply anything about whether the creator takes actions on the open market to try and manipulate the price to be at par.
Circle have $1 which you can redeem each USDC for.
They don't theoretically have extra cash lying around to buy USDC at discount, and they certainly can't use reserves for that (they are needed to serve withdrawals)
Hopefully they do have some corporate cash spare to buy up cheap USDC so that what they lose to SVB doesn't make them insolvent