The tax return is the document an accounting firm handles most often, and also the one people treat as most anonymous: schedules, codes, amounts. A look at what is actually in the schedules shows the opposite.
What it says, line by line
Dependants carry the tax codes of people who have no relationship with the firm, often children. Deductible medical expenses say that someone incurred a medical cost, and in some cases which one. Charitable giving can reveal religious or political affiliations. Property income carries the land registry references of everything owned.
Two of those fall under Article 9 GDPRopens in a new tab: medical expenses are health data, and a donation to a religious body or a political party reveals religious beliefs or political opinions. For those the regime is not stricter, it is different: you start from a prohibition and look for one of the paragraph 2 conditions.
The tax code ends every argument
Even with the names deleted, a return still carries tax codes: the taxpayer’s, the spouse’s, the children’s, the adviser’s. An Italian tax code identifies directly, and it is readable by eye: its letters give the surname, the first name, the date of birth, the sex and the place of birth.
That is why a clean-up done by searching for names is never enough on a tax document. The name goes, and underneath the same person remains, written in a different alphabet.
How to read an Italian tax code
It is worth taking apart, because it is the shortest possible proof that this value cannot be left in. An individual’s tax code is not a serial number handed out by an office: it is computed from the personal details, which means it can be read backwards.
The first three letters come from the consonants of the surname, the next three from those of the first name. Then two digits for the year of birth and a letter for the month. Then two digits for the day, with forty added if the person is female, so the code also declares sex, without anybody having asked. Four characters follow for the municipality of birth, the cadastral code known as the Belfiore code, which for people born abroad gives the country. The last character is a check character.
The upshot is that removing the name and leaving the tax code hides nothing: surname, date of birth, sex and place of birth stay legible sixteen characters further along. It is also why, in a return, the dependants’ tax codes weigh as much as the taxpayer’s: they are the personal details of people who have never set foot in the office.
It is not only the return: the other documents that leave
The tax return is the example, not the perimeter. In any given month a firm handles documents that identify just as well or worse, and it is worth having them in mind, because a written rule holds for all of them or for none.
The means-tested income declaration used for the Italian ISEE is probably the densest document of all: the household’s movable and immovable assets, plus the components covering invalidity and disability, which are Article 9 health data. The inheritance tax return carries the entire family tree, with degrees of kinship, shares and tax codes of people who signed nothing. The withholding agent’s return and the payroll ledger carry the details of every one of a client’s employees. The payment form carries the IBAN. And filings to the tax authority carry the tax code of whoever transmitted them, which is the firm itself.
The practical consequence is that a rule written about “tax returns” covers a third of the problem. The one that holds talks about values rather than documents: names, tax codes, VAT numbers, IBANs, land registry references, dates of birth and addresses do not leave the office in the clear, whatever form they happen to be written on.
What you can actually ask, and how
The useful requests are almost all about form and rules rather than about the person: whether a deduction applies in that situation, how to complete a schedule in an unusual case, what changed since last year, why a calculation does not add up.
None of those needs the real tax code. With identifiers replaced by stable placeholders the relationships stay readable, the spouse is the same spouse across every schedule, and the model can still reason about the case, which is what you wanted.
The bill for the manual route
On a return with dependants and several schedules, cleaning up by hand is slow and fails predictably: it catches the values in the headers and leaves the ones in the attachments and the tables. And when the firm files two hundred of them, the internal rule about cleaning up before pasting holds until the first week of deadlines.
The route that holds is the one where substitution costs thirty seconds and happens on the office computer. Tax codes, VAT numbers and IBANs are verified against their check character rather than recognised by eye (the difference is set out here), the rest is a proposal you confirm, and the real values go back in when the answer arrives.