Per diems are specific amounts of money an organization provides to an individual to cover expenses when traveling for work.  As a best practice, organizations should try to avoid paying per diems, especially to government officials.  Instead, the organization should try to pay trip-related expenses directly to service providers.  Alternatively, the organization can reimburse the individual for any legitimate expenses upon receiving complete documentation of the expense.

If it is not possible for a company to pay service providers directly or reimburse well-documented expenses, and a per diem is necessary, then the same policies that govern per diems for the company’s own employees should apply to government officials traveling at the behest of the company. In either case, the ABC policy should establish who is responsible for approving the provision of a per diem in advance of the relevant trip.  The expenses should be a reasonable approximation of the actual daily expenses for that business trip.  The organization should document the amount of the per diems, who received per diems, and the reasoning used to determine the amount of the per diems.    For more on documentation of travel expenses, see here.  

In evaluating per diems, helpful benchmarks can be found by comparing the rates applicable to government and/or UN employees.  The State Department rates, listed by country, are available here; UN rates are available here.