"This class of riskier corporate debt, also known as junk bonds, has not received the investment-grade stamp of approval from ratings agencies."
David Berman....if you wish to be taken seriously as a business reporter, please do not cite rating agencies when  describing risk. They lost all credibility during the 2008/2009 financial collapse. I couldn't care if they rated something A or Z. Their opinion means nothing, zero, nada! Please find other sources to rate the risk of bonds.