The chart below illustrates the average credit spreads of U.S. corporate bond issues by ratings over U.S. Government Bond yield from June 2009 to October 2020: 5.00 4.50 4.00 3.50 3.00 2.50 2.00 1.50 1.00 0.50 Average % 10-Year Bond Spreads over US Government by Ratings AA 0.81 A 1.08 BBB 1.75 BB 3.54 B 4.42 Explain why there is a substantial jump in bond spreads between BBB and BB rated corporates compared to differences between the other adjacent rating categories. What are bonds rated BB+ or weaker commonly called? Name 4 of the main characteristics typical of the issuers of these bonds?