The US authorities suspect that Ober has used spyware to spy on its competitors, the company said in a statement published by The Wall Street Journal.
The program, known as Hell, was used until last year to track drivers working with rival Levitte, according to the economic news newspaper.
"We are cooperating with the investigation," Ober told Agence France-Presse, confirming that the program was no longer used by the taxi services company without giving further details. "Opber was setting up accounts for Levite's imaginary customers to create its system with passengers looking for drivers to transport them," the Wall Street Journal quoted unnamed sources as saying.
In this way, "Ober would have been able to monitor the 'Lift' drivers in the neighborhood and the prices they are asking for."
The program was also used to gather information on the drivers working for the two companies in a way that would induce contractors to quit their jobs.
The Wall Street Journal said the investigation would determine whether the use of the software was an illegal information breach. Levitte is the main rival of Uber in the United States.
Several investigations have been carried out on the basis of suspicions of corruption or the use of other illegal software used by drivers to evade authorities in areas where the company is prohibited.