Markets certainly are.

OK
Just a little pinprick
There’ll be no more aaaaaaaah!
But you may feel a little sick – Pink Floyd

Hard to say what the pinprick will be. 

My bet is higher inflation and higher interest rates.   

On the other hand, it could be a form of Structured Criticality.  Just one more grain of sand will be all it takes to trigger the avalanche.

Structured criticality is a property of complex systems in which small events may trigger larger events due to subtle interdependencies between elements. This often gives rise to a form of stratified chaos where the general behavior of the system can be modeled on one scale while smaller- and larger-scale behaviors remain unpredictable.

For example:

Consider a pile of sand. If you drop one grain of sand on top of this pile every second, the pile will continue to grow in the shape of a cone. The general shape, size, and growth of this cone is fairly easy to model as a function of the rate at which new sand grains are added, the size and shape of the grains, and the number of grains in the pile.

The pile retains its shape because occasionally a new grain of sand will trigger an avalanche which causes some number of grains to slide down the side of the cone into new positions.

These avalanches are chaotic. It is nearly impossible to predict if the next grain of sand will cause an avalanche, where that avalanche will occur on the pile, how many grains of sand will be involved in the event, and so on.  – Wikipedia