What if corporate-bond buyers focused less on how quickly they could trade the stuff and more on the basic question of, are they actually going to get their money back? Because, in a growing number of cases, they may not. While American companies seem to be in good shape based on a historically low default rate, they look a lot less good if you peek under the hood of their balance sheets. One problematic sign: the least-creditworthy companies have seen pretty much no growth in a basic measure of their earnings, even after stripping out the embattled energy companies, Bank of America Corp. analysts found. Yet these junk-rated corporations are selling debt at a rapid clip to lock in ultra-low borrowing costs, meaning their levels of debt relative to their income are steadily rising. Another problematic sign: creditors of companies that are going bankrupt are getting less of their […]