Global issuance of investment-grade bonds reached almost $3 trillion in 2018, up slightly from 2017 and up almost 400% from 2010. However, the percentage of that debt in relation to all issuances fell to 31%, a sharp decline from 2017's 46%. Investment-grade debt as a proportion of all debt had been in steady decline as the economy recovered from the financial crisis as companies levered up on low interest rates.
Total U.S. corporate debt, ex-financials was about $6.2 trillion as of Sept. 30, 2018, according to data from the U.S. Federal Reserve. Year-over-year growth from 12 months earlier was 2%, a notable contrast from the 6.9% average year-over-year over the five years ended Sept. 30, 2017.