Company: BCDRF
Filing Date: 2025-10-31
Form Type: 424B5
Source: 0001193125-25-260533
Chunk: 151

Company: Banco Santander, S.A.
Filing Date: 2025-10-31
Form: 424B5
Chunk 151
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 and demand for the contingent convertible capital securities of such series; |

| • |     | economic, financial, political or regulatory events or judicial decisions that affect Banco Santander, the Group,                     
 the banking sector or the financial markets generally, including the introduction or amendment of any financial transactions tax; and |

| • |     | the trading price of Banco Santander’s ordinary shares and/or ADSs; |

Accordingly, if holders sell their contingent convertible capital securities of any series in the secondary market, they may not be able to obtain a price equal to the Liquidation Preference of the contingent convertible capital securities of such series or a price equal to the price that they paid for the contingent convertible capital securities of such series. The contingent convertible capital securities are not investment grade and are subject to the risks associated with non-investmentgrade securities. The contingent convertible capital securities of any series, upon issuance, will not be considered to be investment grade securities, and as such will be subject to a higher risk of price volatility than higher-rated securities. Furthermore, deteriorating outlooks for Banco Santander or the Group, or volatile markets, could lead to a significant deterioration in market prices of below-investment grade rated securities such as the contingent convertible capital securities of any series. Credit ratings may not reflect all risks associated with an investment in the contingent convertible capital securities of any series. Ratings may not reflect the potential impact of all risks related to structure, market, additional factors discussed above, and other factors that may affect the value of the contingent convertible capital securities of any series. Similar ratings assigned to different types of securities do not necessarily mean the same thing and any rating assigned to the contingent convertible capital securities of any series does not address the likelihood that Distributions or any other payments in respect of the contingent convertible capital securities of such series will be made on any particular date or at all. Credit ratings also do not address the marketability or market price of securities. 43

Any change in the credit ratings assigned to the contingent convertible capital securities
of any series may affect the market value of the contingent convertible capital securities of such series. Such change may, among other factors, be due to a change in the methodology applied by a rating agency to rating securities with similar
structures to the contingent convertible capital securities of any series, as opposed to any revaluation of Banco Santander’s financial strength or other factors such as conditions affecting the financial services industry generally.

A credit rating is not a recommendation to buy, sell or hold securities and may be revised or withdrawn by the rating