Low-Rated Global Corporate Debt Has Ballooned [pdf]

See Figure 1 in the PDF.

Interesting about this is that companies have apparently borrowed lots of money from financial institutions. At the same time, they were also able to borrow lots of money from the stock market due to high share prices relative to earnings [1] combined with the possibility to sell new shares/hand out options.

[1]: https://www.multpl.com/shiller-pe