“Can the incumbent that paid America's payroll for 75 years become the embedded financial OS for both SaaS platforms and the small businesses they serve?”
ADP began as a manual payroll processor in 1949 and grew into the dominant US payroll outsourcer, paying 1 in 6 American workers. Its embedded finance evolution centers on two flanks: ADP Marketplace (2015) opened the company to third-party HR/fintech integrations, and ADP Embedded Payroll repositioned ADP as an infrastructure provider to SaaS platforms that want payroll-as-a-feature — competing directly with Check, Gusto Embedded, and Salsa. CashFlow Central added embedded SMB bill-pay and invoicing inside RUN, signaling ADP's intent to own more of the small-business financial OS, not just payroll.