If supply chain data beyond what is available in IBISWorld (above) is needed your best local option if you have access to it is the Bloomberg Terminal lab in MSU's School of Business. The SPLC command to map business relationships across suppliers, customers and competitors for companies globally.
Bloomberg Terminals are available to current students in the School of Business.
Please contact your department for information about access.
Please expect to search through trade journals and business news sources that cover the industry in which your company operates. Often these are where reports about new contracts, lost contracts, joint ventures being considered, etc., can be found.
When searching, be sure to be creative in how you describe what you are looking for.
If you need a hand with this, please reach out to the Sprague Library's Research & Reference Librarians for help.
(See chat box above)
Public companies are required to name the companies that they deal with if, and only if, the relationships with those companies may place the reporting company in jeopardy. For example, the reporting company would be in jeopardy if one of their major suppliers, or customers, were having problems or trouble. This is usually discussed in the 10-K report in the Management's Discussion & Analysis section. If the partner company gets into trouble mid-year, it may also be reported in an 8-K report.
EDGAR and Mergent Online will allow the full text searching of SEC filings.
If you're willing to go to them in person (remote access is limited to their students, faculty and staff), the libraries below have other tools that contain supply chain information.
Rutgers University Libraries:
The David and Lorraine Cheng Library at William Paterson University: