American Express Co's (NYSE:AXP) second-quarter revenue (net of interest expense) grew 8% year-on-year to $16.33 billion, slightly missing the analyst consensus estimate of $16.59 billion.  Amex's stock price went up after the report, but it soon gave up the gains in the premarket session on Friday. The increase was primarily due to higher net interest income, increased Card Member spending, and continued strong card fee growth. Adjusted EPS of $3.49 beat the analyst consensus estimate of $3.26.  Card Member spending or Billed Business grew 5% ( or 6% forex adjusted) year-over-year to $388.2 billion.  U.S. Consumer Services revenue was $7.73 billion, up ...