What type of services does American Express primarily provide?

American Express is primarily known for offering a diversified range of credit, prepaid, and charge card services. The company has established itself as a leader in the payment card industry, enabling consumers and businesses to make transactions more efficiently. Their products include traditional credit cards, charge cards that require full payment each month, and prepaid cards.

American Express's business model is centered around facilitating financial transactions for cardholders, and it garners revenue through transaction fees and annual membership fees. This diversity in card offerings allows them to cater to a wide audience, including individuals and enterprise customers who require varied financial solutions.

In contrast, the other choices suggest a limited scope of services. Specifically, American Express is not solely focused on travel-related services, nor does it primarily offer insurance and investment services. Although audit and compliance can be important in the financial sector, they are not the core offerings of American Express. This comprehensive focus on flexible payment card solutions distinguishes American Express and drives its business success.