2025.10.04 – Banamex and CLABE Clarifications, E.164 Telephone Format, and the Meaning of LADA

Summary
This document explains the equivalence between Banamex and Banco Nacional de México, the structure and use of the Mexican CLABE number, and the importance of E.164 formatting for international phone numbers. It also describes the origin and meaning of the term LADA, showing how local and international dialing codes connect within a unified global system.

Context and Scope
The text focuses on two core topics: banking identifiers used in Mexican electronic transfers and the standardization of international telephone numbering. It integrates factual details about Banamex’s identity and the use of CLABE in financial operations, together with a technical explanation of the E.164 recommendation and the linguistic and practical meaning of LADA. The objective is to provide a clear, self-contained reference for accurate data entry and contact formatting.

Exhaustive Narrative of Facts

1. Banamex and CLABE Explained
   Banamex and Banco Nacional de México, S.A. are the same institution. The name Banamex is a contraction of “Banco Nacional de México.” After its separation from Citi in late 2024, Banamex continued as a consumer bank, while “Citibanamex” remained a recognized commercial label. For deposits or transfers, any of these names may appear on forms, but they refer to the same bank.

The CLABE (Clave Bancaria Estandarizada — Standardized Bank Code) is an 18-digit number required for all Mexican electronic funds transfers through the SPEI (Interbank Electronic Funds Transfer System). It uniquely identifies both the bank and the recipient’s account. Western Union and other transfer systems request the CLABE when sending funds directly to a Mexican account.
Key practices include:
– Selecting the correct bank name, preferably “Banco Nacional de México (Citibanamex).”
– Ensuring the beneficiary’s name exactly matches the one registered at the bank.
– Entering the CLABE without spaces or extra symbols.
– Marking the recipient as a private individual, not a business.

2. E.164 Telephone Number Standard and the Meaning of LADA
   E.164 is an international numbering plan defined by the International Telecommunication Union (ITU). The “E.” identifies the ITU’s Series E recommendations concerning network operation and numbering, and “164” is the sequential document number. The standard sets the global structure for all telephone numbers: the plus sign “+” followed by the country code and the national significant number, with a maximum of 15 digits. It excludes local or long-distance prefixes such as 0 or 1, ensuring global consistency and interoperability among networks and digital systems.

E.164 replaced the earlier E.163 plan, extending the maximum length of numbers and standardizing their presentation for both fixed and mobile services. It defined specific elements — Country Code (CC), National Destination Code (NDC), and Subscriber Number (SN) — and explicitly separated dialing prefixes from the actual number.

The term LADA (Larga Distancia Automática — Automatic Long-Distance Dialing) originated in Mexico to describe area codes used for national and international calls. In modern usage, “LADA” refers to a geographic or country prefix. In English, the equivalent terms are “area code” for domestic use and “country code” for international dialing.
When numbers are saved using the E.164 structure, the LADA is represented by the initial country code. For example:
– Mexico: +52 followed by 10 national digits.
– Argentina: +54 followed by the local number, omitting national prefixes.

Practical Takeaways
– Banamex and Banco Nacional de México are the same institution; both names are valid in forms and transfers.
– The CLABE number, composed of 18 digits, is essential for correct Mexican bank deposits.
– E.164 defines the global telephone format using “+country code” and up to 15 digits.
– “LADA” refers to dialing prefixes—domestic or international—and corresponds to the country or area code when stored in E.164 format.
– Using standardized identifiers such as CLABE and E.164 ensures reliable financial transactions and universal phone compatibility.