Spain's new 400 anti-spam prefix already used in scams within a week

The 400 prefix, mandatory for commercial calls in Spain since October 17, does not stop scammers from imitating it: a user in Córdoba reported an attempt to steal banking details from a +400 number posing as Iberdrola.

The rule reserving the 400 prefix for commercial calls in Spain came into force on Saturday **October 17**. Its logic was simple: if the number starts with 400, users know they are being sold something and can decide whether to answer. Less than a week later, the first report of fraudulent use of that same prefix was already on the table.

## A +400 number impersonating Iberdrola

A user in **Córdoba** went to the Local Police to report an attempted phone scam. The call came from a number starting with **+400**, and the caller identified themselves as **Iberdrola** employees. The goal was not to sell a plan: it was to obtain the man's personal and banking details.

The case shows the flip side of the measure. The prefix identifies companies that comply with the rule, but it does not certify who is on the other end of the line. Anyone can dial a number starting with 400, and a phone screen cannot tell a legitimate salesperson from an impostor.

## The Local Police warning

The Local Police stress an idea worth remembering: a call beginning with the **+400** prefix is not guaranteed to be legitimate. Incivil can exploit this numbering to try to deceive people, and they have already done so.

Their advice is the usual, but no less effective for being repeated. Be wary of unexpected calls asking for banking details or information. Never share passwords or card verification codes. And do not rely solely on the number shown on screen, as it can create a false sense of trust. If in doubt, hang up and contact the company through its official channels.

## What the 400 prefix changes and what it does not

The rule requires all commercial calls to be made from a nine-digit number starting with 400. Spain's Minister for Digital Transformation and Public Administration, **Óscar López**, presented it as a way for anyone in Spain to easily identify a sales call and decide whether to answer. Those who break the rule can be reported to the Office for Telecommunications User Services (Oficina de Atención al Usuario de Telecomunicaciones).

What the rule does not do is authenticate the origin of the call. It blocks unregistered spam, just as already happens with SMS, but it does not prevent a scammer from dialing a 400 number and posing as a well-known company. The label helps filter; it does not replace skepticism.

If a call asks for banking details, passwords or verification codes, the prudent thing is to hang up and call the company through its official channel. No serious company closes an urgent transaction over the phone by rushing people.