Tether holds $1.5 billion in BTC
According to Tether's Q1 2023 report, they made a net profit of $1.48 billion. During that time, USDT's capitalization increased from $66 billion to $81 billion.
Tether also disclosed the structure of its reserves, most of which are in U.S. Treasury bonds. But also about $3.3 billion is in precious metals, and $1.5 billion is invested in bitcoin.
And how much money in BTC is held by the USDC... none?