Amid heightened uncertainty about the global economy, all three U.S. indexes are in a bear market as the third quarter comes to a close.
Russia owes interest payments on two dollar-denominated bonds on Wednesday. If it doesn't pay, the country could go into default.
The bond market flashed an ominous warning Friday, as the yield on long-term government debt dipped below that of short-term bills. That unusual situation often signals a recession on the horizon.
Dozens of companies see the value of their high-yield corporate bonds fall, as investors worry they won't be able to pay back what they owe.