The court held that the “test is whether such an inference is sufficiently restrictive to support the conclusion that the property has been “taken from its owner.” The court considered the term “amount” contained in the expropriation clause and held that for a measure to qualify as indirect expropriation it must be equivalent to direct expropriation. The court in Tecmed v. Mexico held that the state measure will be an indirect expropriation if it is permanent and if the investor's rights have been affected in such a way that “any form of exploitation thereof… has disappeared”. In the case of Telenor Mobile Communication AS v Hungary it was held that the investment should be considered as a whole and that expropriation would occur if there was a substantial erosion of value. The court in the Revere Copper case found that indirect expropriation had occurred by examining “the impact on effective control over the use and operation” of the investor's property. Formal ownership of the property was not affected, but the investor's control of its use and operation was no longer effective. Taxation, while involving a clear transfer of assets to the state, is generally considered an exception to laws prohibiting expropriation. However, there are some cases where it can qualify as indirect expropriation. In Occidental v Ecuador, the court stated succinctly that “taxes can lead to expropriation.” In the Feldman case, the court found that “…tax measures, even if targeted and have the effect of expropriation, will be indirect, with an effect that could amount to