In spite of its apparent simplicity, this rule presents many pitfalls for both parties when used for cross-border transactions.
Ex Works obliges the buyer to undertake export procedures (obtaining of licences, security clearances and so on.) The buyer may be poorly placed to do this. In any event the seller is only obliged to “provide assistance”, at the buyer’s risk and expense.
From the seller’s perspective, there is the problem of obtaining evidence that the goods are to be exported – where VAT or sales tax is charged on domestic sales, the tax authorities may require this.
The obvious alternative for cross-border transactions is Free Carrier (FCA) – seller’s premises.