Emery's team have been in talks to buy Real Union for at least 12 months, reports Marca.
Real Union currently compete in Segunda B with a part-time playing staff.
"There is an exchange of information between the parties, but there is still no agreement or principle of agreement on the matter," a source said.
Emery's grandfather played for Real Unión in the 1920s. In fact, Antonio Emery was a player at the start of the LaLiga.
The negotiations are conducted by the law firm of his personal lawyer, Josu Reta, and the brother of the coach, the journalist Igor Emery, who lives in the area and who is driving the project on the ground.