It's important to look past revenue and earnings figures.American Express (AXP +0.74%) is continuing its winning ways. Shares are up 18% in 2025 (as of Oct. 20), outpacing the broader S&P 500. They recently got a lift after the business reported third-quarter revenue and earnings per share that came in ahead of Wall Street estimates. Those two key headline figures are certainly important to pay attention to. However, every American Express investor should keep a close eye on this number. American Express h ...