A big part of today's drop today was the result of Delta Airlines announcements made yesterday regarding their 90% drop in revenue forecast and steps they are taking to cover the millions of dollars per day of cash bleeding.
Precisely why Warren Buffet sold his airline holdings. This is also why Warren Buffet have a large cash position because there is too much risk buying equities for now. I also have a large cash position of 30% equities and 70% treasuries. When there are more sellers than buyers, the stock market decline.