Despite the current rosy picture, there may be trouble ahead.

Most recent numbers published by the Federal Reserve
indicate that U.S. credit cards are growing healthily, with increasing
portfolio value, record low delinquency rates, and stable interest rates,
except for the return on assets (ROA) metric. As we look toward 2017, we expect
steady performance with a focus on more regulatory scrutiny, interest rate
increases, and tighter competition, which will task the sacrosanct ROA.  Unforeseen economic shock could entirely
disrupt the model.