The “prolonged environment of low growth and low interest rates has been a catalyst for striking changes in nonfinancial corporate credit quality,” Mariarosa Verde, Moody’s senior credit officer, said in a report. “The record number of highly leveraged companies has set the stage for a particularly large wave of defaults when the next period of broad economic stress eventually arrives.”
https://www.cnbc.com/2018/05/25/moodys-warns-of-particularly-large-wave-of-junk-bond-defaults.html