Circular SINAP 1-237 National Payments System – Electronic Payment Medium (MEP)

"Año de la Reconstrucción de la Nación Argentina" COMUNICACIÓN “A” 8343 14/10/2025 A LAS ENTIDADES FINANCIERAS, A LAS CÁMARAS ELECTRÓNICAS DE COMPENSACIÓN, A LAS INFRAESTRUCTURAS DEL MERCADO FINANCIERO: Ref.: Circular SINAP 1-237: SISTEMA NACIONAL DE PAGOS - MEDIO ELECTRÓNICO DE PAGOS (MEP)

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We address you to deliver the new consolidated text on the National Payments System – Electronic Payment Medium (MEP) provided in the annex forming part of this communication, in order to update it as follows: − update of section 1.4 regarding operating hours; − incorporation of section 1.5 regarding the administration of the MEP System; − incorporation of the last paragraph of section 4.4 regarding MEP Statements; − update of clause 13 of the mutual adherence agreement model (Section 6.), in accordance with Law 26.994; − update of the list of operations (Section 7.): DM4, DM5 and DE2 were removed, and the following transfer operations were incorporated: Externas ▪ DD9 Payment by financial entities to international organizations; ▪ DPA Third-party transfers – Movements with Special Accounts for Asset Regularization (CERA) - Law 27.743; and ▪ DZV Refund of operations originated at the BCRA – Comm. A 7879. Internas ▪ V01 BCRA – Attachments/Garnishments; ▪ V02 BCRA – Other judicial payments; ▪ V03 BCRA – OI/GN transfers internal account debit - Comm. A 7879; ▪ V05 BCRA – GN transfers to financial entities in pesos - Comm. A 7879; ▪ V09 BCRA – Payments to Liquidated Entities; ▪ V11 BCRA/BNA – Funding of own accounts; and ▪ V30 BCRA – Payment to Suppliers - Comm. A 7879.

-2- − update of the list of entities provided in Section 8. Furthermore, we note that formal adjustments were made in other sections. It is recalled that on this Institution's website www.bcra.gob.ar, by accessing “Financial System – LEGAL AND REGULATORY FRAMEWORK – Organization and summaries – Consolidated texts of general regulations”, the modifications made will be found with text highlighted in special characters (strikethrough and bold). We remain, yours sincerely BANCO CENTRAL DE LA REPUBLICA ARGENTINA Juan C. Navas Matías A. Gutiérrez Girault Gerente de Cuentas Corrientes Gerente Principal de Sistemas de Pago y Cuentas Corrientes a/c ANEXO

-Índice- Sección 1. Generalidades 1.1. Definición 1.2. Objetivos 1.3. Participantes 1.4. Horario operacional 1.5. Administración MEP Sección 2. Requisitos para operar 2.1. Formales 2.2. Técnicos Sección 3. Funcionalidad del Sistema MEP 3.1. Ambiente 3.2. Servicios web Sección 4. Operatorias 4.1. Definición 4.2. Objetivo 4.3. Características 4.4. Extractos MEP 4.5. Alta, modificación, estructuración y pruebas de operatorias MEP 4.6. Manual de operatorias MEP Sección 5. Contingencias en la conectividad con el BCRA 5.1. Requisitos para operar en contingencias 5.2. Comprobación periódica Sección 6. Convenio de adhesión mutua para la transferencia electrónica de fondos entre entidades del sistema financiero Sección 7. Listado de operatorias MEP Sección 8. Listado de entidades adheridas y habilitadas en el MEP Tabla de correlaciones B.C.R.A. TEXTO ORDENADO SOBRE SISTEMA NACIONAL DE PAGOS - MEDIO ELECTRÓNICO DE PAGOS (MEP) Versión: 7a. COMUNICACIÓN “A” 8343 Vigencia: 15/10/2025 Página 1

1.1. Definición The Electronic Payment Medium (MEP) or MEP System allows fund transfers between participants throughout a defined operational cycle, using the accounts they hold open at the Central Bank of the Argentine Republic (BCRA). It is a real-time gross settlement –RTGS– system, through which the settlement of financial intermediation payment instruments between entities is carried out, which may act on their own behalf or on behalf of third parties. Furthermore, it is the only channel for settling balances arising from electronic fund clearing as a result of the interrelation between entities and electronic clearing houses (ECH).

1.2. Objetivos 1.2.1. Establish an information exchange system between the BCRA and participating entities based on message and transaction transfers between computers through a modern, efficient and reliable platform within a security framework. 1.2.2. Optimize the economic flow between entities and contribute to the control of movements recorded in their accounts. 1.2.3. Reduce costs within the financial system. 1.2.4. Contribute to the consolidation and development of the national payments system. 1.2.5. Enhance the possibility of its integration with other systems by improving its operational, security and reliability characteristics.

1.3. Participantes Participating entities are financial institutions, electronic clearing houses, exchange offices, national, provincial, municipal and Buenos Aires City autonomous official bodies, and other entities that, due to the nature of their management within the framework established by national legislation and BCRA regulations, operate in the financial market holding accounts open in their name at the BCRA, additionally meeting the formal and technical requirements requested to operate in the MEP. The list of affiliated and authorized entities to operate through the MEP is found in Section 8. Furthermore, the numbers of their operational accounts at the BCRA are disclosed by the BCRA's Manager of Current Accounts through Communications B. These accounts are grouped into current and special accounts in pesos, and sight accounts in US dollars, euros and other foreign currencies authorized by the BCRA. B.C.R.A. SISTEMA NACIONAL DE PAGOS - MEDIO ELECTRÓNICO DE PAGOS (MEP) Sección 1. Generalidades Versión: 5a. COMUNICACIÓN “A” 8343 Vigencia: 15/10/2025 Página 1

1.4. Horario operacional The MEP System operates on banking days, from 8:00 to 20:00. For clearing operations of balances generated by the transfer of electronic certificates for deposits and time investments (CEDIP), it is available from 7:30. The operating hours may be modified by the BCRA, even in an extraordinary and/or occasional manner. Such modifications will be communicated to system participants through usual communication channels (communications, bulletins, messaging channel, etc.).

1.5. Administración MEP The administration of the MEP System corresponds to the Sub-Manager of Payment Medium Administration, while account management and signature registration are handled by the Sub-Manager of Current Accounts; both sub-managers report to the Manager of Current Accounts. Participants may communicate with the operational administration of the MEP System through the email addresses mep@bcra.gob.ar and/or gestiondeoperatorias@bcra.gob.ar. Furthermore, inquiries related to current accounts must be sent to the email address ctas.ctes@bcra.gob.ar. B.C.R.A. SISTEMA NACIONAL DE PAGOS - MEDIO ELECTRÓNICO DE PAGOS (MEP) Sección 1. Generalidades Versión: 5a. COMUNICACIÓN “A” 8343 Vigencia: 15/10/2025 Página 2

To access the facilities provided by the MEP application, participating entities must meet the following requirements: 2.1. Formales 2.1.1. Signing of the “Mutual Adherence Agreement for the Electronic Transfer of Funds between Entities of the Financial System of the Argentine Republic”, whose model is set forth in Section 6. The entity requesting adherence to the MEP must submit a memo at the BCRA's Reception Desk, on official letterhead –in original and copy–, addressed to the Manager of Current Accounts, which must bear two signatures registered at the BCRA. Attached to the memo and in a closed envelope, it must include the Mutual Adherence Agreement (provided for in Section 6.) in original and a copy. The signatory/signatories of the agreement must be authorized before the Manager of Current Accounts to carry out fund movements, fully respecting the usage modality instructed by each financial entity in said department. The BCRA Reception Desk will return the annotated copy of the memo, with the assigned file number. The Manager of Current Accounts, upon receiving the file, will proceed to verify the documentation. If not in compliance with what is established, it may reject adherence by clearly notifying the reasons, so that the applicant regularizes the situation and can proceed with the procedure. The act will be formalized once the Agreement is signed by the competent BCRA authority –in original and copy–, after which the Manager of Current Accounts will deliver a copy of the Agreement personally or as an attachment to a memo addressed to the applicant entity. 2.1.2. Comply with legal and/or formal obligations and current regulations established by the BCRA's General Sub-Manager of Systems and Organization regarding the minimum technical requirements and specifications that data links of MEP adherents must meet for access and use of resources and applications, designation of security and communication officers, delivery of passwords, assignment