The answers on this question are naive and harmful. It is common for contractors, agencies, etc to negotiate for keeping the IP of what they work on. Many busin

The answers on this question are naive and harmful. It is common for contractors, agencies, etc to negotiate for keeping the IP of what they work on. Many businesses use this as a tactic to convert from a services company to a product company. There is no straling or unethical behavior at play here. If you can reach an agreement with your client, everything is fine. Just make sure to have a lawyer draw up the contract, as it sounds like you haven't done this kind of arrangement before.