The decline of the combined market cap of the three largest stables started with Tether at the time when the implosion of Terra/Luna happened. While USDT was falling, the market cap of USDC received a last push higher.
USDT ATH market cap $91 billion , on 21.12.23
USDC ATH market cap $56,2 billion, 01.07.22 down to $24,8 billion on 21.12.23
BUSD ATH market cap $23,5 billion, 15.11.22 down to $1,1 billion on 21.12.23
