Thus, the question to be asked is whether the tax is imposed "on all transactions of the relevant kind without differentiation based on the source or destination of the goods", and if the tax refers to a particular market, the material factor is the effect of the tax on transactions in that particular market.
Thus, the query concerns whether the tax is imposed uniformly on all relevant transactions without differentiation based on their source or destination, and if it relates to a specific market, the material factor is the impact of the tax on transactions in that particular market.