5b20a255__2010___The_Board_of_Directors__Potential_impact
[Issue] The Group may be unable to collect balances due from any client that files for bankruptcy or becomes insolvent. [How it is managed] Evaluating and monitoring clients’ ongoing creditworthiness and in some cases requiring credit insurance or payments in advance. [Potential impact] 
The Group is generally paid in arrears for its services. Invoices are typically payable within 30 to 60 days. The Group commits to media and production purchases on behalf of some of its clients as principal or agent depending on the client and market circumstances. If a client is unable to pay sums due, media and production companies may look to the Group to pay such amounts to which it committed as an agent on behalf of those clients.
WPP Annual Report 2010 - The Board of Directors