Co-op Financial Services, operator of one of the nation's largest surcharge-free ATM networks for credit unions, says the network is growing. The Rancho Cucamonga, Calif.-based network announced that 68 credit unions joined in the third quarter for the three-month period, ending Sept. 30. Bill Prichard, Co-op spokesperson, did not disclose comparable data for the same three-month period last year, saying that it was "proprietary information." Prichard explained, however, that "more than double" number of credit unions joined Co-op Financial Services surcharge-free ATM network in 2009's third quarter compared with 2008's third quarter. Co-op Financial Services operates a network of 28,000 surcharge-free ATMs for member credit unions. When credit unions join Co-op Financial Services, their ATMs become part of the network. In order to the join Co-op Financial Services, a credit union must have at least one ATM, Prichard says.