Brokerages on the Chinese mainland and in Hong Kong are preparing the staff and technology needed to launch a pilot cross-border stock trading program, but industry insiders said it's premature to predict the impact on either market until more policy details are announced.

Several brokerages said that the Shanghai Stock Exchange had asked brokerages to submit applications by Friday to participate in the pilot program. The notice told participating brokerages to finish technology and support-staff preparations before the end of July.

The Shanghai and Hong Kong exchanges announced in April the Hong Kong-Shanghai Stock Connect program, which will allow investors to trade eligible shares in each other's market. The program is expected to start in October.