The market's favorite recession indicator just flashed its biggest warning since 2007

The spread between two- and 10-year Treasury yields is below zero, an occurrence that's preceded each of the past seven recessions.
This so-called yield-curve inversion has happened multiple times over the past couple of weeks, but the spread fell on Tuesday to its most negative level since March 2007.
While yield-curve inversions have preceded all recessions since 1950, when exactly a recession might occur is still unclear.
Read more on Markets Insider.
A continued rally in long-term US Treasur