Onstar's Official Terms and Conditions:

THE INFORMATION WE GET FROM YOUR CAR INCLUDES THINGS SUCH AS DATA ABOUT ITS OPERATION,
ABOUT YOUR USE OF OnStar SERVICES, ABOUT WHERE YOUR CAR IS JUST BEFORE AND DURING REQUESTS FOR OnStar SERVICE IN YOUR CAR, AND (DEPENDING ON YOUR OnStar Equipment) DATA ABOUT ACCIDENTS INVOLVING YOUR CAR (for example, the direction from which your car was hit).

You agree that we can, subject to applicable law, use any of this information to: (a) provide OnStar services to you or your Car (including sharing that information with roadside assistance providers, emergency service providers, or others, as needed);

(b) check or maintain your OnStar Equipment;
(c) provide information to the maker of your Car about the Car's performance and to enable the maker of your Car to comply with law;
(d) help you or managers of fleets of Cars (if your Car is part of a fleet) to maintain the Car;
(e) evaluate and improve our service;
(f) enforce this agreement with you or others;
(g) prevent fraud or misuse of OnStar service;
(h) comply with legal requirements, valid court orders and exigent circumstances;
(i) protect the rights, property, or safety of you or others;
(j) offer you new or additional products or services; or
(k) perform market research.