PACRA rating process

[CBPian]

Every credit rating agency CRA has its own algorithm to rate an instrument, entity or a country. The tools used include past and current financial data, cashflows of the company, its relative standing, environment assessment and a host of other variables which are factored as risk weights. I do not think you can use some checklist or formulae to arrive at the same rating given by a certain CRA due to the fact that these are kept confidential and the alphabet assignment is merely a matter of choice of the CRA, however one can perform one's own rating by looking at various factors affecting the issue of the instrument and the entity's ability to service the debt.
Have a look at this informative article
http//www.icraindia.com/services/rating/r-credit.htm#1
you can also visit S&P and Moody's websites to view various credit ratings and legends to rating assignments.