The Bank for International Settlements in Basel is the worldwide central banks' joint organization. The BIS annual report is usually a good read on global monetary and credit conditions, chock-full of data.
The 2017 report includes a section on so-called zombie firms, companies whose weak balance sheets and performance would have led to bankruptcy in a higher interest rate environment. It is possible that low interest rates and zombie firms could be part of the puzzle of persistent low productivity growth.
The Bank for International Settlements is an international financial institution owned by central banks which "fosters international monetary and financial cooperation and serves as a bank for central banks".