The charity, which employs about 2,500 staff, was registered in April under the temporary name Age UK.
It is expected to unveil its new public name within weeks, and a spokesman confirmed Agenda was under active consideration.
"It is being looked at and staff have been consulted on it," he said. But no final decision has been taken yet.
Brand consultancy Corporate Edge was hired in January to create the new identity. Chris Wood, its chair, said older people's needs would be central to the branding strategy.
The merged charity's spokesman said it had so far paid Corporate Edge less than £100,000.