Junk bonds, risky corporate assets, are a good measure of risk on - risk off. In this case, we have plotted the long term "safe haven" of a 20+ year maturity versus JNK. Take note, when this ratio turns down, the NYSE Index also turns down. There was one case where the ratio decoupled so do take that into account but take a look at the next three charts. Certainly looks like JNK is about to turn down and if turns down w/ a vengeance (is this the last leg of a 5 leg triangle a-b-c-d-e?) then equities will follow close behind.
