There is this thing called the VIX. Some people call it the fear gauge. It was invented to measure people's expectations about how much the stock market is going to bounce around.
At some point, the VIX went from measuring expectations about the stock market. To being something people bet on.
Then, last week, when the market plunged, the role of the VIX may have gotten even larger: This thing that was invented to measure the stock market may have started driving the market itself.
On today's show, Tracy Alloway of Bloomberg News tells us the story of the VIX.