Corporate bond issuance couldn't outpace equity growth

There were about $6.5 trillion in non-financial corporate bonds at the end of 2019, a number that steadily increased over the past 15 years at an average clip of 1.3% each quarter. The percentage of that debt relative to equity market value was about 30%, below the 35% quarterly average since 2010. The decline in debt's share relative to equities is more a testament to equity's run-up in the fourth quarter and debt's generally upward trajectory over the past five years — more so when the high rate of corporate share buybacks are considered.

Debt issuance grew exponentially in the years following the global financial crisis as low rates made debt an attractive option. Rating agencies took notice of the rising debt issuance, rating a larger portion of that debt below investment grade.

March's 20%-plus decline in global equities will lead to an increase in debt's market-value percentage compared to equities. In March 2009, the market value of non-financial company bonds was two-thirds that of equity market value.