First Source Solutions, formerly ICICI, announced 300 new jobs at their Londonderry call centre this month.
The call centre has been offered £6.7million of support from Invest NI, for the investment.
But a First Source intradepartmental email, seen by the Sentinel, suggests a customer has not been been confirmed for the new Londonderry jobs.
First Source responded that they could not discuss specific client details.
"According to our specific business needs we expect that our business will grow, whether its from existing clients or new clients" a spokesperson said.
"The new jobs are in line with our business plan and progress over the next two years. It is not going to create the jobs immediately but recruit gradually over a transitional period of 2 years.
"What we announced on May 1st that it was our intention to expand and we are absolutely confident that it will happen. We have a thriving business already in Derry and a business plan that we will add to that over the next two years."
The email also suggests that First Source's primary client, Sky have expressed interest in expanding in Londonderry. But Sky denied any connection to the new jobs planned for the call centre.
A Sky spokesperson said : "We have a very good relationship with First Source and we have around 400 people working with us but this expansion is not Sky- related. There is no Sky connection to the new jobs."