Banco Santander Mexico S A Institución de Banca Múltiple Grupo Financiero Santander Mexico : MÉXICO ANNOUNCES THAT IT HAS BEEN DESIGNATED A LEVEL III DOMESTIC SYSTEMICALLY IMPORTANT FINANCIAL INSTITUTION BY THE MEXICAN NATIONAL BANKING AND SECURITIES COMMISSION FOR THE SIXTH CONSECUTIVE YEAR (Form 6-K)

BANCO SANTANDER MÉXICO ANNOUNCES THAT IT HAS BEEN DESIGNATED A LEVEL III DOMESTIC SYSTEMICALLY IMPORTANT FINANCIAL INSTITUTION BY THE MEXICAN NATIONAL BANKING AND SECURITIES COMMISSION FOR THE SIXTH CONSECUTIVE YEAR

Mexico City, Mexico, May 27^th, 2021 - Banco Santander México, S.A., Institución de Banca Múltiple, Grupo Financiero Santander México (BMV: BSMX; NYSE: BSMX) ('Banco Santander México' or the 'Bank') one of the leading banking institutions in Mexico, announced that it has been designated a Level III - Domestic Systemically Important Financial Institution by the Mexican National Banking and Securities Commission (the 'CNBV') for the sixth consecutive year.

The capital buffer applicable to Banco Santander México remains at 1.20%, in addition to a regulatory capitalization ratio of 10.5%. This capital buffer could be built progressively over a maximum period of four years starting 2016. Banco Santander México had constituted 100% of the capital preservation supplement required since its designation as a domestic systemically important bank in that year.

With the current capital indicators including the additional capital preservation supplement requirement, Banco Santander México reported a capitalization ratio of 19.73% as of March 31, 2021. Thus, Banco Santander México already complies with this regulatory requirement.

ABOUT BANCO SANTANDER MÉXICO (NYSE: BSMX; BMV: BSMX)

Banco Santander México, S.A., Institución de Banca Múltiple, Grupo Financiero Santander México (Banco Santander México), one of Mexico's leading banking institutions, provides a wide range of financial and related services, including retail and commercial banking, financial advisory and other related investment activities. Banco Santander México offers a multichannel financial services platform focused on mid- to high-income individuals and small- to medium-sized enterprises, while also providing integrated financial services to larger multinational companies in Mexico. As of March 31, 2021, Banco Santander México had total assets of Ps.1,748 billion under Mexican Banking GAAP and more than 19.0 million customers. Headquartered in Mexico City, the Company operates 1,352 branches and offices nationwide and has a total of 22,280 employees.

Investor Relations Contacts

Héctor Chávez López - Managing Director - IRO

+ 52 (55) 5269-1925

hchavez@santander.com.mx

Investor Relations Team

investor@santander.com.mx

Cautionary Statement on Forward-Looking Statements

This press release contains forward-looking statements. The forward-looking statements contained herein include, without limitation, statements about the intent, belief, targets or current expectations concerning the future business development and performance of Banco Santander México. While these forward-looking statements represent our judgment and current expectations concerning the development of our business, a number of risks, uncertainties and other important factors could cause actual developments and results to differ materially from our expectations. Information relating to risks, uncertainties and other factors that affect our business are included in our annual report on Form 20-F filed with the U.S. Securities and Exchange Commission. The risks and uncertainties included in our filings and reports, including those with the U.S. Securities and Exchange Commission, could adversely affect our business and financial performance. You should not place undue reliance on these forward-looking statements, which speak only as of the date they were made, and we undertake no obligation to update publicly or to revise any forward looking statements, except as required by applicable law.