Frequently recommended companies that conduct searches for a fee. Does not imply endorsement.
The University of Delaware Library does not have any unique information on stocks, even for companies incorporated in Delaware.
The incorporation files at the state of Delaware, Division of Corporations are online.
Select "Search for a Business Entity" from the division's home page (https://www.corp.delaware.gov/).
Many useful resources are widely available in libraries around the country, especially in public and university libraries.
The above guides list many resources to consult. This list are the resources available at the University of Delaware Library.