COB

Close of Business refers to the end of the business day, typically used as a deadline for submissions, responses, or actions. COB times vary by location and may be specified as Eastern Time, local time, or contracting office time.

Understanding COB deadlines is critical for timely proposal submissions and contract compliance. Government solicitations specify submission deadlines that may use COB or specific times. Late submissions are generally rejected. Contractors should clarify timezone interpretations and submit well before COB to avoid technical issues.