The market share of 30 % provided for in Article 3(1) shall be calculated on the basis of the market sales value of the contract goods or services and other goods or services sold by the supplier, which are regarded as interchangeable or substitutable by the buyer, by reason of the products' characteristics, their prices and their intended use; if market sales value data are not available, estimates based on other reliable market information, including market sales volumes, may be used to establish the market share of the undertaking concerned. For the purposes of Article 3(2), it is either the market purchase value or estimates thereof which shall be used to calculate the market share.
