My research on lease requirements took me back to a NIF requirement. It’s confusing because English speakers and translation apps use different terms for what may be the same thing. Here is one law firms definition of a ‘Tax Representative’, the same term I posted earlier in the translated version of the Portuguese law: “The Tax Representative is legally responsible for receiving their fees, property taxes, inform the taxpayer of all tax obligations, and ensure that payment is made within the designated time limits.”
I found this definition of Fiador on a Portuguese site selling business and tax advice (google translate converted fiador to guarantor): “The legal status of the “guarantor” is regulated in the civil codes (and not in commercial legislation). In this regard, in general, it is said that the bond is a contract by which a person agrees with the creditor to pay for the debtor, if he does not (although the guarantor can, in the contract, waive his right to order). That is, the guarantor will respond to the creditor only if the debtor does not do so.”
I read that as a Tax Representative’s role is between Financias (AKA The Tax Man ) and the person seeking a NIF. A Fiador is what is called in the US a co-signer. He’s responsible for the debts of the person using him as a Fiador.
I made a long post about this on one expat forum asking for feed back and links to support the feedback. Got nothing. I’m going to post it on other expat and FB forums. If and when I get results, I’ll post back here.