There are three main credit rating agencies – S&P, Moodys and Fitch. Each has their own rating scale with S&P ( and Fitch ) using a combination of letters and +/- , the best rating is AAA, then AA+, AA, AA – and so on all the way down to C. Investment grade rating stop at BBB-, and junk/high yield starts at BB+; Moodys uses a combination of letters and numbers. Ultimately they all map to a probability of default ( the point at which the creditors, normally banks and bond holders will call in the receivers to try and get there money back. )
The key point here is if they fail their debt covenants ( normally defined in terms of interest coverage ) the debt holders ( normally Banks ) will come in and either liquidate the company or force a sale to new investors ( if they can find anyone) .
The fact that they are so highly leveraged ( lots of debt ) suggests that they are probably owned by one of the private equity funds , who will cut their loses if they can’t see a future where they can make money – the one thing they won’t care about is the people who have already bought the products