Credit cards are one of the major ways that consumers hold debt. It can also fluctuate to a greater extent on an individual basis than would be expected from student loans, auto loans, or home mortgages.
Fortunately, on an aggregated basis, it's behavior isn't particularly volatile and provides a good metric to assess one aspect of debt-burden faced by consumers:
While large banks see delinquency behavior in line with the market (which would be expected as large banks comprise most of the market), smaller banks show a different behavior:
Overall, we can use these indicators to gauge the current and future potential of consumer purchasing ability.