The short answer
Our sponsors provide ranges of funding and can partner in a variety of ways (unrestricted gifts, research grants, licensing, investment, etc). Should a sponsor be interested in funding your proposal through a research grant, then indirect costs can be included in the total funding amount.
The longer, more nuanced answer
Based on each individual project, the sponsor will assess the amount of funding necessary for its successful completion. Typically the sponsor will consider indirect costs when determining this amount. For example, if the sponsor estimates the researcher will need $100,000 and the indirect costs at the university are 50%, it would provide $150,000.
Every sponsor is different, however, and how each determines the appropriate amount of funding can vary by RFP and by the project itself. If a sponsor reaches out to you about your proposal and this is a concern, we suggest asking the sponsor if it considers indirect costs when determining the final funding amount.
And some more nuance
Some opportunities on Halo (e.g. Bayer's Grant4Ag program) are structured as "unrestricted gifts" and not sponsored research. Typically indirect costs are not required by universities for unrestricted gifts. We recommend connecting with your office of sponsored research to confirm.