When and why does the Principal Investigator sign a Commitment Form?

PIs need to sign a Commitment Form when they are committing cash from existing research funding or research time (if eligible) in an application, institutional letter, or agreement. 

Any fund holder is required to sign the Commitment Form to ensure sufficient documentation of their cash contributions to the project. Similarly, Commitment Forms are used to ensure that in-kind contributions are approved by those with the authority to make those contributions. This applies to the PI, where you are committing their own research funds and research time (if eligible) to a project.