This article looks at stock valuation of AmEx, Discover and Capital One, but also offers an inside look at account holders buying-spending stats.
Quotes from the article (brief quotes)
Increased card member spending resulted in record American Express first quarter revenues and earnings.
While Capital One customers purchase more on average with their cards than Discover, Capital One extends credit to lower quality borrowers
and does not process payments.
Despite a reasonable valuation, Discover remains a second-tier credit provider whose customers do not spend much and have credit problems.
http://seekingalpha.com/article/547651-amex-remains-golden-standard-of-lucrative-credit-card-industr...
