I don't believe that this inherently true. The market generally revoles around risk, additional returns are possible when taking more risk. Higher rates of issu

I don't believe that this inherently true. The market generally revoles around risk, additional returns are possible when taking more risk. Higher rates of issuance just mean that there is more availability and possibly drive the prices down due to supply. Now, a lower rating would result in a hirer interest, as lower ratings means higher risk (at least in theory, but what this article actually shows is that this isn't the case).