There is no legal requirement, that I am aware of, requiring a signature.Generally, it is a function of company policy.  However, I will say that it was a requirement in all of the companies I've ever worked for.The implication is that your signature represents that you are authenticating that all of the receipts submitted for reimbursements were legitimate business expenses and comply with the company's expense reimbursement policies.Some companies may have an automated system whereby expenses are put onto a personal (rather business) credit card, which are 'sponsored' by the company...