In early 1966, UPI acquired the assets and key personnel of a similarly named (but previously unrelated) competing service, Radio Press International.
Out of that merger came an audio service that at its peak served more than a thousand U.S. radio stations and many foreign clients, including other networks such as NPR, RKO, Britain's Independent Radio News and even CNN in its early years when CNN, then headed by former UPI and UPTN executives Reese Schonfeld and Burt Reinhardt, effectively reunited UPI audio with UPITN video.
Unlike most commercial radio networks, which usually paid local stations to air their programming (and commercials), UPI charged stations cash for its broadcast services, allowing them to sell their own advertising within or adjacent to UPI broadcasts.
After a long period of changing ownerships, business models and bankruptcies, UPI declined into a shell of a news service by 1999, when its then-Saudi Arabian ownership was convinced by its handpicked CEO, Arnaud de Borchgrave, to exit the broadcasting business United Press had pioneered back in the 1930s.
The rump UPI sold its client list of its radio network and broadcast wire to its former rival, the AP.