Market bull and bear trends, as well as real liquidity, cannot be judged by price alone; we also need to look at the bidding activity of funds. The APY of USDT deposits on exchanges is the most direct indicator. When the market is highly active, borrowing demand surges, and USDT deposit APYs can reach 15%. In extreme cases, they can spike over 50% in a short period. After a sharp decline, trading volume shrinks, everyone tightens their wallets, borrowing demand drops significantly, and APYs also fall back, with some even lower than the yields on U.S. Treasury bonds during the same period.