Goldman Sachs is preparing to roll out a bond-trading platform on which it will charge lower fees than on typical bond trades, according to people familiar with the matter, a move that could help retain customers tempted by rival trading venues being set up by BlackRock and others.

The New York securities firm has been developing an electronic platform called GSessions over the past year, according to a person familiar with its plans. The idea is to bring together clients who want to buy or sell specific corporate bonds at certain times, a process known as "crossing trades."