Stripe’s secondary-market valuation has risen sharply to the $180–184 billion range in recent months on robust revenue growth and positioning in AI-driven agentic payments, including its OpenRouter acquisition, while American Express trades at a roughly $208 billion market cap. This narrow 54.5% edge for Stripe reflects the contrast between its high-multiple private-market momentum and Amex’s more stable but slower-expanding public valuation amid credit-services sector dynamics. Key swing factors include Amex’s October 23 earnings release, ongoing secondary trading prints for Stripe shares, and any shifts in broader fintech or AI adoption trends that could alter implied multiples before year-end.