I thought bond and treasury yields were supposed to be stable till maturity date.
Yet we often see reports like this:
Market upheaval intensified Friday as stocks and oil prices tumbled, while investors seeking shelter in haven assets pushed the yield on long-term U.S. government bonds to unprecedented levels. The yield on the benchmark 10-year Treasury note fell below 0.7% for the first time.
From WSJ's "Bonds Extend Rally as U.S. Stocks Decline" on March 6, 2020
Why do bond and treasury yields drop as more people invest in them?