The expense recharge question
You fly to Amsterdam for a client workshop. You buy a software licence your client needs. You hire a specialist subcontractor. In each case, you pay the cost, then rebill it to the client. The question is: do you charge VAT on the amount you rebill?
The answer depends on how the EU VAT Directive classifies the arrangement. Article 73 establishes the general principle: "The taxable amount shall include everything which constitutes consideration obtained or to be obtained by the supplier, in return for the supply, from the customer or a third party, including subsidies directly linked to the price of the supply." If the expense recharge is part of the consideration for your supply, it is subject to VAT.
The Directive then provides two paths. Article 78(b) includes incidental expenses in the taxable amount. Article 79(1)(c) excludes amounts paid as reimbursement of expenditure incurred "in the name and on behalf of the customer." The distinction between these two paths is the principal vs agent question — and it determines the entire VAT treatment.