In times of great uncertainty or upheaval, markets fluctuate up and down pretty wildly. Everybody realizes it should adjust to some new value to reflect the ne

In times of great uncertainty or upheaval, markets fluctuate up and down pretty wildly. Everybody realizes it should adjust to some new value to reflect the new reality. But nobody knows what that value is. So nobody is sure if the market has adjusted too far or not enough. So any time any new information comes in, people grasp at straws trying to make sense of the situation (and/or decide they have to act despite very limited information), and the market goes up and down. It doesn't just move smoothly in one direction and then gradually come to a stop once it finally reaches the new "correct"(-ish) value. It jerks back and forth as it gets there. So even when down is the inevitable direction, it's going to have a few ups mixed in.