For tax purposes, TNI operates with fiscal number 0034.74.082. It pays taxes on salaries.

TNI is not considered an enterprise and, as such, is exempt from charging and paying VAT, save where clearly commercial activities might be involved. TNI undertook one consultancy in 2021 on which VAT was charged and paid over to the tax authorities.

TNI is acknowledged by the Dutch tax authorities as an organisation that works for the general interest (ANBI: Algemeen Nut Beogende Instelling). This allows those who make donations to TNI to qualify for tax rebates within the European Union.

TNI has long been formally recognized as holding the equivalent of 501 (c) status in the US. This status is reconfirmed annually with a certificate that may be used by members of NGOSource.