FORM 6-K SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Report of Foreign Issuer Pursuant to Rule 13a-16 or 15d-16 of the Securities Exchange Act of 1934 For the month of October, 2023 Commission File Number: 001-12518 Banco Santander, S.A. (Exact name of registrant as specified in its charter) Ciudad Grupo Santander 28660 Boadilla del Monte (Madrid) Spain (Address of principal executive office) Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F: Form 20-F ☒ Form 40-F ☐

BANCO SANTANDER, S.A. ________________________ TABLE OF CONTENTS Item 1. January - September 2023 Earnings presentation

Earnings Presentation — 9M’23 25 October 2023

2 Important information Non-IFRS and alternative performance measures This presentation contains financial information prepared according to International Financial Reporting Standards (IFRS) and taken from our consolidated financial statements, as well as alternative performance measures (APMs) as defined in the Guidelines on Alternative Performance Measures issued by the European Securities and Markets Authority (ESMA) on 5 October 2015, and other non-IFRS measures. The APMs and non-IFRS measures were calculated with information from Grupo Santander; however, they are neither defined or detailed in the applicable financial reporting framework nor audited or reviewed by our auditors. We use these APMs and non-IFRS measures when planning, monitoring and evaluating our performance. We consider them to be useful metrics for our management and investors to compare operating performance between periods. APMs we use are presented unless otherwise specified on a constant FX basis, which is computed by adjusting comparative period reported data for the effects of foreign currency translation differences, which distort period-on-period comparisons. Nonetheless, the APMs and non-IFRS measures are supplemental information; their purpose is not to substitute IFRS measures. Furthermore, companies in our industry and others may calculate or use APMs and non-IFRS measures differently, thus making them less useful for comparison purposes. APMs using ESG labels have not been calculated in accordance with the Taxonomy Regulation or with the indicators for principal adverse impact in SFDR. For further details on APMs and Non-IFRS Measures, including their definition or a reconciliation between any applicable management indicators and the financial data presented in the consolidated financial statements prepared under IFRS, please see the 2022 Annual Report on Form 20-F filed with the U.S. Securities and Exchange Commission (the SEC) on 1 March 2023 (https://www.santander.com/content/dam/santander-com/en/documentos/informacion-sobre-resultados-semestrales-y-anuales-suministrada-a-la-sec/2023/sec-2022-annual-20-f-2022-en.pdf), as well as the section “Alternative performance measures” of Banco Santander, S.A. (Santander) Q3 2023 Financial Report, published on 25 October 2023 (https://www.santander.com/en/shareholders-and-investors/financial- and-economic-information#quarterly-results). Underlying measures, which are included in this document, are non-IFRS measures. The businesses included in each of our geographic segments and the accounting principles under which their results are presented here may differ from the businesses included and local applicable accounting principles of our public subsidiaries in such geographies. Accordingly, the results of operations and trends shown for our geographic segments may differ materially from those of such subsidiaries. Non-financial information This presentation contains, in addition to financial information, non-financial information (NFI), including environmental, social and governance-related metrics, statements, goals, commitments and opinions. NFI is included to comply with Spanish Act 11/2018 on non-financial information and diversity and to provide a broader view of our impact. NFI is not audited nor reviewed by an external auditor. NFI is prepared following various external and internal frameworks, reporting guidelines and measurement, collection and verification methods and practices, which are materially different from those applicable to financial information and are in many cases emerging and evolving. NFI is based on various materiality thresholds, estimates, assumptions, judgments and underlying data derived internally and from third parties. NFI is thus subject to significant measurement uncertainties, may not be comparable to NFI of other companies or over time or across periods and its inclusion is not meant to imply that the information is fit for any particular purpose or that it is material to us under mandatory reporting standards. NFI is for informational purposes only and without any liability being accepted in connection with it except where such liability cannot be limited under overriding provisions of applicable law. Forward-looking statements Santander hereby warns that this presentation contains “forward-looking statements” as per the meaning of the U.S. Private Securities Litigation Reform Act of 1995. Such statements can be understood through words and expressions like “expect”, “project”, “anticipate”, “should”, “intend”, “probability”, “risk”, “VaR”, “RoRAC”, “RoRWA”, “TNAV”, “target”, “goal”, “objective”, “estimate”, “future”, “commitment”, “commit”, “focus”, “pledge” and similar expressions. They include (but are not limited to) statements on future business development, shareholder remuneration policy and NFI. However, risks, uncertainties and other important factors may lead to developments and results to differ materially from those anticipated, expected, projected or assumed in forward-looking statements.

3 Important information The following important factors (and others described elsewhere in this presentation and other risk factors, uncertainties or contingencies detailed in our most recent Form 20-F and subsequent 6-Ks filed with, or furnished to, the SEC), as well as other unknown or unpredictable factors, could affect our future development and results and could lead to outcomes materially different from what our forward-looking statements anticipate, expect, project or assume: (1) general economic or industry conditions (e.g., an economic downturn; higher volatility in the capital markets; inflation; deflation; changes in demographics, consumer spending, investment or saving habits; and the effects of the war in Ukraine or the COVID-19 pandemic in the global economy) in areas where we have significant operations or investments; (2) climate-related conditions, regulations, policies, targets and weather events; (3) exposure to various market risks (e.g., risks from interest rates, foreign exchange rates, equity prices and new benchmark indices); (4) potential losses from early loan repayment, collateral depreciation or counterparty risk; (5) political instability in Spain, the UK, other European countries, Latin America and the US; (6) legislative, regulatory or tax changes (including regulatory capital and liquidity requirements), especially in view of the UK´s exit from the European Union and increased regulation prompted by financial crises; (7) acquisition integration challenges arising from deviating management’s resources and attention from other strategic opportunities and operational matters; (8) our own decisions and actions including those affecting or changing our practices, operations, priorities, strategies, policies or procedures; (9) uncertainty over the scope of actions that may be required by us, governments and others to achieve goals relating to climate, environmental and social matters, as well as the evolving nature of underlying science and industry and governmental standards and regulations; and (10) changes affecting our access to liquidity and funding on acceptable terms, especially due to credit spread shifts or credit rating downgrades for the entire group or core subsidiaries. Forward looking statements are based on current expectations and future estimates about Santander’s and third-parties’ operations and businesses and address matters that are uncertain to varying degrees, including, but not limited to developing standards that may change in the future; plans, projections, expectations, targets, objectives, strategies and goals relating to environmental, social, safety and governance performance, including expectations regarding future execution of Santander’s and third-parties’ energy and climate strategies, and the underlying assumptions and estimated impacts on Santander’s and third-parties’ businesses related thereto; Santander’s and third-parties’ approach, plans and expectations in relation to carbon use and targeted reductions of emissions; changes in operations or investments under existing or future environmental laws and regulations; and changes in government regulations, regulatory requirements and internal policies, including those related to climate-related initiatives. Forward-looking statements are aspirational, should be regarded as indicative, preliminary and for illustrative purposes only, speak only as of the date of this presentation, are informed by the knowledge, information and views available on such date and are subject to change without notice. Santander is not required to update or revise any forward-looking statements, regardless of new information, future events or otherwise, except as required by applicable law. Not a securities offer This presentation and the information it contains does not constitute an offer to sell nor the solicitation of an offer to buy any securities. Past performance does not indicate future outcomes Statements about historical performance or growth rates must not be construed as suggesting that future performance, share price or results (including earnings per share) will necessarily be the same or higher than in a previous period. Nothing in this presentation should be taken as a profit and loss forecast. Third Party Information In this presentation, Santander relies on and refers to certain information and statistics obtained from publicly-available information and third-party sources, which it believes to be reliable. Neither Santander nor its directors, officers and employees have independently verified the accuracy or completeness of any such publicly-available and third-party information, make any representation or warranty as to the quality, fitness for a particular purpose, non-infringement, accuracy or completeness of such information or undertake any obligation to update such information after the date of this presentation. In no event shall Santander be liable for any use by any party of, for any decision made or action taken by any party in reliance upon, or for inaccuracies or errors in, or omission from, such publicly-available and third-party information contained herein. Any sources of publicly-available information and third-party information referred or contained herein retain all rights with respect to such information and use of such information herein shall not be deemed to grant a license to any third party.

4 Index 9M'23 Highlights & progress on our strategy 1 Final remarks 3 Appendix 42 Group review

5 Strong 9M results with 9mn new customers YoY contributing to a double-digit revenue increase ONE TRANSFORMATION driving efficiency improvement and profitable growth Delivering double digit value creation and rising shareholder remuneration 9M'23 highlights Cash DPS Q3 Attributable Profit +20% vs. Q3’22 €2.9bn EPS YoY TNAVps + DPS YTD 9M Attributable Profit €8.1bn +11% YoY RoTE +126bps YoY 14.8% FL CET1 12.3% +0.2pp YoY CoR 1.13% Further strengthened our balance sheet, with solid credit quality metrics and higher capital ratio +39% YoY +12% +0.14pp YTD Note: In constant euros: 9M Attributable Profit +13% YoY; 9M Revenue +13% YoY; Q3 Attributable Profit +26% vs. Q3’22. TNAVps + DPS includes the €5.95 cent cash dividend paid in May 2023 and the €8.10 cent cash dividend approved in September that will be paid in November 2023. +17%

6 Profit increased in 9M'23, supported by customer revenue and efficiency improvement, with double-digit growth in net operating income 2,543 2,351 2,422 2,289 2,571 2,670 2,902 Q1'22 Q2 Q3 Q4 Q1'23 Q2 Q3 € mn Attributable profit Attributable profit (Constant € mn) +9% QoQ +20% 2,613 2,285 2,331 2,261 2,549 2,655 2,939 P&L Constant € million 9M'23 9M'22 % NII 32,139 28,460 13 Net fee income 9,222 8,867 4 Other income 1,734 1,302 33 Total revenue 43,095 38,629 12 Operating expenses -18,961 -17,595 8 Net operating income 24,134 21,034 15 LLPs -9,037 -7,491 21 Other results* -2,321 -1,782 30 Attributable profit 8,143 7,316 11 Current 38 13 % 16 6 14 13 10 16 21 Note: Underlying P&L. (*) Including the temporary levy in Spain (-€224mn) in Q1’23.

7 Revenue1 Efficiency ratio CoR FL CET1 RoTE 9M'232023 targets On track to deliver on our 2023 financial targets Double-digit growth 44-45% <1.2% >12% >15% +13% 44.0% 1.13% 12.3% 14.8% Note: targets market dependent. Based on macro assumptions aligned with international economic institutions. (1) YoY change in constant euros.

8 FL CET1 TNAVps + Cash DPS € per share 4.26 4.75 Dec-22 Sep-23 3 Interim distribution in Nov-23 Cash dividend per share of €8.10 cents +39% YoY Current share buyback programme4 €1,310mn Building up capital organically and delivering double-digit value creation with higher shareholder remuneration Since 2021 and including the full current share buyback authorized, Santander will have repurchased c.9% of its outstanding shares (1) Gross organic generation net of regulatory charges and other charges. (2) Impact corresponding to cash dividend accrual (33 bps) and buybacks (36 bps) announced during the first nine months of the year. Execution of the shareholder remuneration policy is subject to future corporate and regulatory decisions and approvals. (3) TNAVps + DPS includes the €5.95 cent cash dividend paid in May 2023 and the €8.10 cent cash dividend approved in September that will be paid in November 2023. (4) Amount equivalent to c. 25% of the Group’s underlying profit in the first half of 2023. The implementation of the remainder of the shareholder remuneration policy for 2023 is subject to the appropriate corporate and regulatory approvals. 12.3 -0.69 12.0 +0.92 Dec-22 Net organic generation Shareholder remuneration Sep-23 % 1 2 +0.3pp +12%

9 Improving efficiency due to the execution of One Transformation and extracting value from our Global & Network businesses • Multi-Latin/Multi-European: +53% 9M’23 revenue YoY growth • WM&I: collaboration with CIB and Corporates $160mn YTD (+13%) • Auto: expansion of OEM agreements • Global approach to technology: c.€124mn efficiencies YTD - Gravity (back-end) efficiencies - Global vendor agreements - IT&Ops shared-services • Product simplification: 8% fewer products YTD • 55% products/services digitally available: +10pp YTD • In US, c.$114mn efficiencies captured YTD in Consumer and Commercial 200-250 bps c. 42% 100-150 bps 50-75 bps -117 bps -39 bps -29 bps FY’22 One Transformation Global & Network businesses Global Tech capabilities & others 2025 target 9M’23 45.8% FY’22 45.8% Execution YTD Efficiency Reminder from Investor Day Efficiency 44.0% 9M’23 or latest available data.

10 One Transformation driving simplification, reducing cost to serve and increasing transactionality 9M’23 data (or latest available). Changes in constant euros Process automation Best-in-class Tech PlatformSimplification Cost1 per active customer -2% Revenue per active customer YoY +11% YoY Transactions per active customer +12% # Operational FTEs per mn customers -5% YTD YoY Debit Global Cards platform completed Gravity Deployed in 3 countries and SCIB 75bn Transactions YTD SCIB (1) In real terms.

11 Global and Network businesses: revenue growing above Group 9M'23 data. Changes in constant euros ID Targets (CAGR 22-25) Total revenue €3.0bn +27% Network revenue SCIB c.10% WM&I PB network AuMs €52bn +12% c.10% Payments # Transactions 26bn +15% PagoNxt c.30% PagoNxt Auto Auto loans and leases €179bn +7% c.7% +23% -4%+21% +22% 1 Note: total transactions include merchant payments, cards and electronic A2A payments. (1) It includes all fees generated by asset management and insurance businesses, even those ceded to the commercial network.

12 Progressing towards our 2025 profitability targets Europe South America North America Digital Consumer Bank Group DCB 2025 Target9M'23 SCIB WM&I RoTERoTE EBITDA Margin 2025 Target9M'23 2025 Target9M'23 19.6% >30% 1 14.8% c.15% 10.4% c.15% 14.8% c.19% 11.3% c.15% 14.8% 15-17% 28.4% >20% 92.1% c.60% (1) Adjusted RoTE: US adjusted based on Group’s deployed capital calculated as contribution of RWAs at 12%.

13 Index 9M'23 Highlights & progress on our strategy 1 Final remarks 3 Appendix 42 Group review

14 43,095 -24337,997 +2,777 +1,115 +784 +151 +514 9M'22 Retail SCIB WM&I PagoNxt Auto CC 9M'23 Total revenue Double-digit revenue growth backed by good customer activity across businesses and regions Revenue trends • >95% of total revenue is customer related which drives the vast majority of total revenue growth • Good margin management in a context of higher interest rates in Europe and solid fee performance in North and South America • Strong revenue increase YoY with all businesses growing double-digits except auto: - Retail +12% driven by higher NII (Europe and Mexico) and net fee income (South America and Mexico) - SCIB up 21%, supported by good performance across products, especially transactional business - WM&I increased 22%, mainly driven by NII from strong commercial activity, interest rates and insurance fees - PagoNxt grew 23% backed by good merchant performance - Auto remained affected by negative interest rate sensitivity • Higher liquidity buffer remuneration and lower negative impact from FX hedging in the Corporate Centre Group performance By business NII + Fees Other income Constant € mn YoY growth +15% Total revenue 1 +12% +22%+21% +23% -4% +13% 12,517 12,467 13,014 13,431 13,889 14,219 14,987 Q1'22 Q2 Q3 Q4 Q1'23 Q2 Q3 Note: Retail excluding Auto and fees ceded to commercial network. Breakdown by business following Investor Day criteria. (1) It includes all fees generated by asset management and insurance businesses, even those ceded to the commercial network. Total revenue

15 8,976 9,232 9,577 10,062 10,090 10,647 11,402 Q1'22 Q2 Q3 Q4 Q1'23 Q2 Q3 2.45% 2.52% 2.56% 2.56% 2.63% 2.74% 2.82% NII and NIM up YoY, supported by volumes and margin improvement NII drivers • NII growth of 7% in the quarter • NII growing YoY in Europe and North America: - Europe (+32%) and Mexico (+13%), driven by positive sensitivity to interest rates - DCB (+5%) as volume growth and active loan repricing offset negative interest rate sensitivity - South America trends turning positive • NIM consistently improving QoQ, driven by asset repricing and contained cost of deposits • Positive NII sensitivity ahead of guidance, reflecting the strength of our European franchises, mostly funded with stable retail deposits NII Margins Net interest income and NIM NIM Quarterly NII Constant € mn 2.73% -1.19 -0.08 2.51% +1.34 +0.15 9M'22 Asset yields Asset volumes Liability costs Liability volumes 9M'23 NIM +19% Note: NIM = NII / Average earning assets. Changes in constant euros.

16 2,849 2,949 2,898 2,931 3,027 3,036 3,160 Q1'22 Q2 Q3 Q4 Q1'23 Q2 Q3 Net fee income grew driven by customer activity and value-added products, with 42% of total fees from Global and Network businesses YoY % changes in constant euros Net fee income drivers Constant € mn Net fee income 9,222 -3 8,696 +173 +220 +35 +77 +24 9M'22 Retail SCIB WM&I PagoNxt Auto CC 9M'23 Retail SCIB WM&I • Active customers increased by 2.1mn YoY • Transactionality and well-targeted services to segments • Double-digit growth across regions and businesses • Strengthening value-added services • Private Banking CAL increased 14% YoY • SAM: third quarter in a row with positive net sales • Insurance gross written premiums grew 5% YoY YoY growth +15% Auto • Increased activity across the board • Good performance in Mexico and the US PagoNxt • Strong total payments volume growth (+24% YoY) backed by Brazil, Europe and Mexico +1% +12%+5% +5% +9% +6% Note: Retail excluding Auto and fees ceded to commercial network. Breakdown by business following Investor Day criteria. (1) It includes all fees generated by asset management and insurance businesses, even those ceded to the commercial network. 1

17 5,553 5,719 5,902 6,294 6,101 6,298 6,563 Q1'22 Q2 Q3 Q4 Q1'23 Q2 Q3 45.0% 46.0% 45.6% 46.6% 44.1% 44.3% 43.6% 18,961 17,174 +425 +348 +857 +147 +11 9M'22 Europe North America South America DCB CC 9M'23 Focus on One Transformation and efficiency, resulting in positive jaws Costs and efficiency driversCosts Constant € mn Costs (-0.5% in real terms1) YoY growth in real terms1 Efficiency Quarterly Efficiency improved • Transformation towards simpler and more integrated models keeps driving efficiency improvements • Transformation investments (technology) in 9M’23 reached €1.8bn • 9M'23 Group efficiency improved 1.5pp YoY to 44.0% mainly driven by Europe (-6.3pp) Costs • Slightly down in real terms • Flat in Europe, DCB affected by strategic growth initiatives • North America performance reflecting our efforts to accelerate transformation and growth • South America growing below inflation despite impacts from salary agreements and tech investments +10% (1) Costs in real terms exclude the impact from weighted average inflation. -0% +2% -2% +1% -0%

18 2,184 2,601 2,695 3,000 2,892 2,888 3,257 Q1'22 Q2 Q3 Q4 Q1'23 Q2 Q3 0.77% 0.83% 0.86% 0.99% 1.05% 1.08% 1.13% Credit quality remains robust, on track to achieve Group 2023 CoR target Credit quality drivers Group NPL and stages • Credit quality remains robust supported by record low unemployment in most countries • NPL ratio stood at 3.13% (3.08% Sep-22) with NPL coverage and stages fairly stable • Most of the Group’s provisions (76%) are related to retail1 CoR Constant € mn LLPs LLPs and credit quality • Spain credit quality remains under control with NPL and CoR improving YoY • CoR in the UK and DCB slightly up from very low levels in Sep-22 • Poland impacted by CHF mortgages YoY • Mexico CoR up YoY at comfortable levels • US CoR (1.77%) up, in line with expectations • Brazil: NPL and CoR improved again QoQ Detail by country Sep-22 Jun-23 Sep-23 NPL ratio 3.08% 3.07% 3.13% Coverage ratio 70% 68% 68% Stage 1 €1,030bn €1,011bn €1,002bn Stage 2 €70bn €75bn €77bn Stage 3 €36bn €35bn €36bn Other credit quality metrics Note: Provisions to cover losses due to impairment of loans in the last 12 months / average customer loans and advances of the last 12 months. (1) Excluding Auto.

19 555 249 153 204 Customer funds 336 162 138 248 133 Customer loans Diversified commercial banking model funded with stable retail deposits SCIB SMEs & Corp Consumer & others Auto Individual mortgages Loan portfolio and customer funds Sep-23 SMEs, Corp & Other SCIB Mutual funds +5%€1,017bn €1,160bn-2% -4% +8% +5% -11% +3% Individual +3% +9% +11% Individuals Sep-23 Time 31% Insured >80% Total deposits1 Deposits from individuals Total deposits by product Transactional c.75% Deposit structure -2% Note: Management breakdown. YoY % changes in constant euros. (1) % transactional deposits under LCR criteria.

20 CET1 well above our target of >12%, driven by strong capital generation, with profitable front-book growth >15% RoTE % % RWAs with RoRWA > CoE Asset rotation and risk transfer activities RWAs mobilized vs. total RWAs 10% Q3’23 FL CET1 performance Maximize capital productivity Front book pricing RoRWA of new book 2.7% Sep-23 estimates 84% (1) Execution of the shareholder remuneration policy is subject to future corporate and regulatory decisions and approvals. 12.5 12.3 -0.12 -0.13 -0.21 12.2 +0.45 +0.04 Jun-23 Gross organic generation Cash dividend accrual Regulatory & models Markets & others Share buyback Sep-23 1

21 Index 9M'23 Highlights & progress on our strategy 1 Final remarks 3 Appendix 42 Group review

22(1) vs. 2022 interim cash dividend. Well-positioned to create shareholder value and deliver sustainable profitability 9M'23 >12% FL CET1 14.8 RoTE +17% EPS +12% TNAVps + DPS YTD Completed our changes to a simpler & more integrated model through ONE TRANSFORMATION that will accelerate efficiency and profitable growth Our resilient balance sheet and stronger capital base, create strong foundation for growth, value creation and shareholder remuneration These results, together with the strong business momentum we see coming into the fourth quarter, put us on track to achieve our 2023 targets We increased our profitability YoY, supported by customer growth and double-digit increase in revenue +39%1 Cash DPS The execution of our strategy and the progress we are making with our global platforms, together with our in-country leadership, make us confident that we can continue to grow the business and increase profitability

23 Index 9M'23 Highlights & progress on our strategy 1 Final remarks 3 Appendix 42 Group review

24 Appendix Investor Day 2025 targets summary and our last step towards ONE SANTANDER Primary and Secondary segments Reconciliation of underlying results to statutory results Glossary The other information in the Appendix regularly provided each quarter can be found in the document entitled "Supplementary Information", published together with this presentation on the Group's corporate website

25 Profitability RoTE (%) 13.4 14.8 15-17 Payout (Cash + SBB)1 (%) 40 50 50 EPS Growth (% CAGR 22-25) 23 17 Double-digit Customer centric Total customers (mn) 160 166 c.200 Active customers (mn)2 99 101 c.125 Simplification & automation Efficiency ratio (%) 45.8 44.0 c.42 Network contribution Global & network businesses’ contribution to total revenue (%) >30 38 >40 Global & network businesses’ contribution to total fees (%) c.40 42 >50 Customer activity Transactions volume per active customer (%)3 - +12 c.+8 Capital FL CET1 (%) 12.0 12.3 >12 RWA with RoRWA>CoE (%) 80 84 c.85 ESG4 Green financed raised & facilitated (€bn) 94.5 105.9 120 Socially responsible Investments (AuM) (€bn) 53 64 100 Financial inclusion (# People, mn) - 1.3 5 Women in leadership positions (%) c.29 30.8 35 Equal pay gap (%) c.1 - c.0 (1) Target payout defined as c.50% of group reported profit (excluding non-cash, non-capital ratios impact items), distributed in approximately 50% in cash dividend and 50% in share buybacks. Execution of the shareholder remuneration policy is subject to future corporate and regulatory decisions and approvals. (2) Those customers who meet transactionality threshold in the past 90 days. (3) Total transactions include merchant payments, cards and electronic A2A payments. (4) Not taxonomy. Green finance raised & facilitated (€bn): since 2019. Financial inclusion (#people, mn): starting Jan-23. Does not include financial education. 2022 2025 targets9M'23 One Transformation driving double-digit growth in value creation TNAVps+DPS (Growth YoY) Double-digit growth average through-the-cycle +6% +10%

26 We recently completed our last step towards ONE SANTANDER, creating a simpler, more efficient operating model PagoNxt & Cards, 2 global payments platforms Bring global merchants & SMEs (Getnet / OneTrade) into a single infrastructure DCB as a first step in personal finance Bring together our digital bank and SCF ONE Transformation for three countries Now globally for all individuals and self employed First Global business Build a global platform sharing one single infrastructure across our footprint Forged a new Global business Promote a service model for clients, leveraging Group scale and capabilities SCIB WM&I Payments DCB Retail 2017 2021 2015 2021 2022 Global product factory / infrastructure Global SMEs, Corporates & Institutional factories along with Retail Commercial 2023Our journey began in 2015 with SCIB leading the way

27 Appendix Investor Day Targets summary and our last step towards ONE SANTANDER Primary and Secondary segments Reconciliation of underlying results to statutory results Glossary The other information in the Appendix regularly provided each quarter can be found in the document entitled "Supplementary Information", published together with this presentation on the Group's corporate website

28 Primary segments Detail by region and country

29 Europe Highlights Note: 9M'23 data and YoY changes (loans, deposits and mutual funds in constant euros). • On track to achieve our key transformation projects such as One App, tech commonality and shared services • Customer growth continued in the region (+970k YoY) • Loans affected by lower demand from companies and early repayments, particularly in mortgages. Deposits flat YoY and +2% QoQ with a significant migration to time deposits • Double-digit profit growth supported by strong NII backed by margin management, positive balance sheet sensitivity to higher interest rates and solid CIB performance. Efficiency gains and active risk management • Positive trends continued QoQ as profit rose 21% fuelled by asset repricing, disciplined deposit pricing and cost control Key data and P&L Loans Deposits Mutual Funds Efficiency CoR RoTE €552bn -7% €609bn 0% €101bn +9% 41.1% -6.3pp 0.44% +8bps 14.8% +5.6pp Underlying P&L* Q3'23 % Q2'23 9M'23 % 9M'22 % 9M'22¹ NII 4,222 5.9 11,787 32.1 31.0 Net fee income 1,084 0.5 3,328 -3.2 -3.3 Total revenue 5,765 8.5 16,228 23.0 22.3 Operating expenses -2,291 2.9 -6,673 6.8 6.0 Net operating income 3,474 12.5 9,555 37.6 37.0 LLPs -662 2.0 -1,951 10.9 10.8 Attributable profit 1,640 21.3 4,176 48.7 47.2 (*) € mn and % change in constant euros. (1) % change in current euros.

30 Spain UK España and UK Note: 9M'23 data and YoY changes (loans, deposits and mutual funds in constant euros). • Strong YoY growth in customers (+744k) and stable deposits. Loan volumes affected by prepayments and lower demand • Profit +68% driven by higher NII, boosted by active pricing management in a context of interest rates hikes, efficiency gains and strong risk metric improvements • Similar trends QoQ: higher NII and lower LLPs • Higher rates continued to affect loan volumes, while deposits were flat YoY with a higher weight of saving accounts • Profit up YoY supported by NII, on the back of higher rates, good cost control and CoR at low levels • Profit QoQ affected by higher LLPs impacted by the update of housing market outlook. Net operating income up 13% Loans Deposits Mutual Funds €238bn -5% €220bn 0% €7bn +1% 48.2% -1.6pp 0.12% +10bps 14.0% +2.7pp Loans Deposits Mutual Funds €231bn -10% €306bn 0% €75bn +5% 40.1% -8.4pp 0.62% -9bps 14.7% +7.3pp Efficiency CoR RoTEEfficiency CoR RoTE Underlying P&L* Q3'23 % Q2'23 9M'23 % 9M'22 NII 1,741 2.4 4,903 56.4 Net fee income 635 -4.0 2,047 -5.7 Total revenue 2,678 4.4 7,791 28.6 Operating expenses -1,088 6.1 -3,127 6.3 Net operating income 1,591 3.3 4,664 49.6 LLPs -377 -3.1 -1,180 -3.9 Attributable profit 722 8.4 1,854 68.0 (*) € mn and % change. Underlying P&L* Q3'23 % Q2'23 9M'23 % 9M'22 % 9M'22¹ NII 1,344 2.2 3,927 9.3 6.3 Net fee income 97 13.6 264 -8.1 -10.6 Total revenue 1,486 5.7 4,245 8.3 5.3 Operating expenses -684 -2.0 -2,047 4.8 1.9 Net operating income 803 13.3 2,198 11.7 8.7 LLPs -126 186.5 -229 0.6 -2.2 Attributable profit 425 -0.6 1,243 12.3 9.2 (*) € mn and % change in constant euros. (1) % change in current euros.

31 Portugal and Polonia Portugal PolandPoland Note: 9M'23 data and YoY changes (loans, deposits and mutual funds in constant euros). • Loan volumes under pressure from higher rates. Excellent liquidity management, with cost of deposits under control, in a context of early redemption of loans • Profit +68% YoY with strong NII, costs under control, significant efficiency gains and robust credit quality • Net operating income rose 53% QoQ backed by solid revenue. Profit QoQ benefited from Q2 regulatory charges • Loans increased mainly driven by consumer lending, SMEs and corporates. Deposits grew across segments • Profit up YoY supported by revenue (NII – active funding cost management) and efficiency improvement, which allowed us to absorb additional CHF mortgage provisions • Profit up QoQ mainly driven by revenue growth and lower CHF provisions €32bn +2% €42bn +10% €4bn +33% 26.5% -2.1pp 1.98% +91bps 18.9% +8.8pp Loans Deposits Mutual Funds Loans Deposits Mutual Funds Underlying P&L* Q3'23 % Q2'23 9M'23 % 9M'22 NII 439 40.0 1,014 96.6 Net fee income 117 5.3 352 -3.7 Total revenue 575 37.2 1,398 49.9 Operating expenses -137 3.2 -401 6.7 Net operating income 438 52.9 997 79.1 LLPs -25 20.7 -59 532.4 Attributable profit 283 100.0 604 67.6 (*) € mn and % change. €38bn -7% €36bn -10% €4bn +10% 28.7% -11.6pp 0.17% +29bps 23.1% +9.9pp Efficiency CoR RoTE Efficiency CoR RoTE Underlying P&L* Q3'23 % Q2'23 9M'23 % 9M'22 % 9M'22¹ NII 662 5.3 1,871 28.8 31.3 Net fee income 148 1.9 437 6.2 8.3 Total revenue 835 6.0 2,344 29.2 31.7 Operating expenses -217 3.9 -622 19.7 22.0 Net operating income 617 6.8 1,722 33.0 35.6 LLPs -132 -32.2 -475 60.8 63.9 Attributable profit 208 33.9 529 126.4 130.8 (*) € mn and % change in constant euros. (1) % change in current euros.

32 • Focus on the most profitable segments and on promoting Group network collaboration • Attracting new customers, supported by our enhanced customer experience through tailored products and services • Strong performance in loans and deposits in both countries • Revenue growing YoY driven by NII (interest rates and volumes) and fees in Mexico, which more than offset higher funding costs in the US • Costs affected by transformation and strategic growth investments, partially offset by cost control initiatives • Profit impacted by LLP normalization in retail portfolios and seasonality in Auto in the US, in line with expectations Note: 9M'23 data and YoY changes (loans, deposits and mutual funds in constant euros). North America Loans Deposits Mutual Funds €165bn +4% €143bn +10% €29bn -4% 48.0% +1.0pp 1.91% +79bps 10.4% -1.2pp Efficiency CoR RoTE Underlying P&L* Q3'23 % Q2'23 9M'23 % 9M'22 % 9M'22¹ NII 2,602 3.2 7,533 3.0 6.1 Net fee income 560 -1.4 1,637 6.6 12.9 Total revenue 3,391 1.8 9,807 5.5 8.7 Operating expenses -1,648 4.1 -4,707 8.0 11.1 Net operating income 1,743 -0.3 5,100 3.3 6.6 LLPs -1,077 47.4 -2,608 52.6 56.6 Attributable profit 554 -25.0 1,900 -19.0 -16.4 (*) € mn and % change in constant euros. (1) % change in current euros. Highlights Key data and P&L

33 •Successful customer attraction strategy reflected in strong YoY growth in customers (+708k), loans (+5%) and deposits (+17%) •Excellent profit and profitability performance supported by double-digit revenue growth, improved efficiency and low CoR •Positive revenue trends continued in Q3 • Stable and diversified deposit base growing 8% YoY (time deposits). Lending up driven by Auto, Multifamily and CIB • YoY and QoQ profit trends affected by LLP normalization (in line with expectations) and transformation costs. • Excluding transformation costs, profit and RoTE aligned with expectations, on track to reach ID target returns Note: 9M'23 data and YoY changes (loans, deposits and mutual funds in constant euros). (2) Adjusted RoTE: adjusted based on Group’s deployed capital calculated as contribution of RWAs at 12%. Using tangible equity, RoTE is 7.4%. USA y Mexico Mexico €49bn +5% €46bn +17% €17bn +2% 42.7% -1.6pp 2.34% +48bps 17.6% +1.0pp €117bn +4% €97bn +8% €12bn -10% 49.9% +3.4pp 1.77% +89bps 11.3% -7.5pp Loans Deposits Mutual Funds Loans Deposits Mutual Funds Efficiency CoR RoTE2 Efficiency CoR RoTE Underlying P&L* Q3'23 % Q2'23 9M'23 % 9M'22 % 9M'22¹ NII 1,414 -1.5 4,314 -3.2 -5.1 Net fee income 189 -5.4 579 0.5 -1.5 Total revenue 1,818 1.2 5,442 -2.0 -4.0 Operating expenses -915 3.2 -2,714 5.1 3.0 Net operating income 903 -0.8 2,728 -8.2 -10.0 LLPs -764 73.8 -1,769 63.0 59.8 Attributable profit 198 -45.8 865 -40.8 -41.9 (*) € mn and % change in constant euros. (1) % change in current euros. Underlying P&L* Q3'23 % Q2'23 9M'23 % 9M'22 % 9M'22¹ NII 1,186 9.8 3,213 12.5 25.7 Net fee income 356 -0.3 1,019 9.8 22.6 Total revenue 1,555 2.6 4,318 16.7 30.4 Operating expenses -681 5.6 -1,845 12.6 25.7 Net operating income 874 0.3 2,473 20.0 34.1 LLPs -312 6.1 -834 34.5 50.2 Attributable profit 403 -3.3 1,163 19.1 33.1 (*) € mn and % change in constant euros. (1) % change in current euros. US

34 South America Note: 9M'23 data and YoY changes (loans, deposits and mutual funds in constant euros). • We are focusing on increasing the value added to the Group and promoting synergies across our global and regional businesses • Customer growth (c.7.5mn YoY) and higher transactionality • Solid performance in loans, deposits and mutual funds with a strengthened risk model • Profit down YoY due to rising costs and LLPs. Revenue up backed by higher NII, fees and gains on financial transactions, which more than offset negative impact of hyperinflation adjustment • Profit QoQ benefited from positive top line, which more than offset cost increase with LLPs fairly stable €162bn +5% €137bn +12% €70bn +21% 39.1% +2.8pp 3.30% +19bps 14.8% -5.2pp Loans Deposits Mutual Funds Efficiency CoR RoTE Underlying P&L* Q3'23 % Q2'23 9M'23 % 9M'22 % 9M'22¹ NII 3,356 11.7 9,833 8.2 0.0 Net fee income 1,264 9.5 3,659 18.1 9.2 Total revenue 4,604 5.7 13,641 6.2 0.2 Operating expenses -1,798 8.0 -5,332 19.1 8.0 Net operating income 2,806 4.3 8,310 -0.7 -4.2 LLPs -1,301 0.7 -3,841 7.0 5.7 Attributable profit 871 42.3 2,329 -15.8 -19.2 (*) € mn and % change in constant euros. (1) % change in current euros. Highlights Key data and P&L

35Note: 9M'23 data and YoY changes (loans, deposits and mutual funds in constant euros). Brazil • Growth in loans (individuals and SMEs) and deposits (time) • Profit down YoY affected by negative NII sensitivity, lower gains on financial transactions (lower market activity), inflation and higher provisions. Fees up driven by transactionality • In Q3, strong NII and fee performance with controlled costs, lower level of LLPs and lower losses in other results Chile • Continued business transformation to offer the best products and services • Profit YoY impacted by negative NII sensitivity. Solid performance in fees (payments & insurance), costs (-8% in real terms) and CoR • QoQ impacted by lower revenue with costs and provisions fairly stable Brasil and Chile Loans Deposits Mutual Funds Loans Deposits Mutual Funds €101bn +3% €89bn +12% €54bn +16% 34.8% +3.7pp 4.67% +21bps 13.7% -6.9pp €44bn +2% €29bn -2% €10bn +16% 45.5% +7.4pp 0.87% -0bps 14.1% -7.5pp Efficiency CoR RoTEEfficiency CoR RoTE Underlying P&L* Q3'23 % Q2'23 9M'23 % 9M'22 % 9M'22¹ NII 2,327 5.3 6,612 -1.3 -0.9 Net fee income 902 3.6 2,577 6.5 6.8 Total revenue 3,336 2.0 9,616 -0.9 -0.6 Operating expenses -1,138 -0.5 -3,345 10.8 11.2 Net operating income 2,197 3.3 6,271 -6.2 -5.9 LLPs -1,121 -2.3 -3,284 3.4 3.7 Attributable profit 603 70.1 1,426 -29.9 -29.6 (*) € mn and % change in constant euros. (1) % change in current euros. Underlying P&L* Q3'23 % Q2'23 9M'23 % 9M'22 % 9M'22¹ NII 241 -26.9 968 -34.5 -32.8 Net fee income 133 -12.8 449 28.4 31.7 Total revenue 465 -19.7 1,694 -14.6 -12.4 Operating expenses -251 0.1 -771 2.0 4.6 Net operating income 214 -34.6 922 -24.9 -22.9 LLPs -84 4.2 -287 -3.6 -1.1 Attributable profit 87 -47.0 417 -26.3 -24.4 (*) € mn and % change in constant euros. (1) % change in current euros.

36Note: 9M'23 data and YoY changes (profit, loans, deposits and mutual funds in constant euros). Argentina • #1 NPS, with one of the best rated apps among local banks • Profit up YoY driven by strong revenue growth and efficiency improvement • Solid performance in Q3 across P&L lines Argentina y Uruguay • Focus on digital expansion in Uruguay and on joint initiatives between CIB and Corporates in Peru and Colombia • Profit up YoY on the back of c.25% revenue growth in all three countries • High profitability: double-digit RoTEs Uruguay, Peru and Colombia Loans Deposits Mutual Funds 22 9M'23 62 9M'23 131 9M'23 Uruguay Peru Colombia RoTEs € mn Attributable profit +29% +19% +11% €6bn +150% €9bn +114% €5bn +194% 49.7% -7.6pp 4.09% +121bps 39.5% +17.7pp 23.5% +2.2pp 23.2% +1.0pp 15.1% -2.1pp Efficiency CoR RoTE Underlying P&L* Q3'23 % Q2'23 9M'23 % 9M'22 % 9M'22¹ NII 629 69.8 1,767 236.0 31.1 Net fee income 164 80.3 446 156.6 0.2 Total revenue 543 68.5 1,572 185.0 11.2 Operating expenses -260 60.4 -781 147.3 -3.5 Net operating income 283 77.1 791 235.5 30.9 LLPs -47 50.3 -143 246.4 35.2 Attributable profit 154 104.8 406 345.6 73.9 (*) € mn and % change in constant euros. (1) % change in current euros.

37 • We continue to reinforce our leadership in mobility though new strategic alliances, our leasing & subscription businesses • Leasing contracts grew +17% YoY, consumer financing including BNPL grew 5%. New lending up 5% (+7% in auto) • Revenue up 6% YoY and 7% QoQ, driven by NII as we actively reprice loans and grow customer deposits to compensate interest rate sensitivity and higher funding costs. Fees impacted by regulatory changes • We are investing in transforming the model (new leasing and BNPL platforms) and business growth (acquisition of MCE Bank Germany). Costs rose 1% in real terms • CoR normalizing and remains at low levels (inc. CHF provisions) Note: 9M'23 data and YoY changes (loans and customer funds in constant euros). Digital Consumer BankDCB New lending Loans Customer Funds €40bn +5% €131bn +9% €70bn +18% 48.3% +0.7pp 0.60% +17bps 11.3% -1.4pp Efficiency CoR RoTE Underlying P&L* Q3'23 % Q2'23 9M'23 % 9M'22 % 9M'22¹ NII 1,069 5.3 3,110 4.6 2.6 Net fee income 210 3.4 604 -3.5 -3.9 Total revenue 1,411 7.0 4,069 6.4 4.7 Operating expenses -652 -0.7 -1,967 8.1 6.1 Net operating income 759 14.5 2,103 4.8 3.4 LLPs -225 0.7 -640 52.6 49.2 Attributable profit 302 8.5 823 -7.8 -9.4 (*) € mn and % change in constant euros. (1) % change in current euros. Highlights Key data and P&L

38 Corporate Centre • NII improved significantly driven by the higher liquidity buffer remuneration as a result of the rising interest rates • Lower negative FX hedging impact resulted in lower losses on financial transactions • Slight decrease in LLPs and other provisions Underlying P&L* 9M'23 9M'22 NII -124 -510 Gains/losses on financial transactions -473 -624 Operating expenses -283 -272 LLPs and other provisions -101 -121 Tax and minority interests -50 -25 Attributable profit -1,084 -1,583 (*) € mn. Highlights Income statement

39 Secondary segments Detail on CIB, WM&I, PagoNxt and Card businesses

40 Corporate & Investment Banking Note: 9M'23 data and YoY changes (revenue lines and commercial activity in constant euros). (2) It includes all fees generated by asset management and insurance businesses, even those ceded to the commercial network. Wealth Management & Insurance • Strong growth in contribution to Group profit (+26% YoY) in a capital-light business, reflected in an RoTE of 92% • Attributable profit +62% YoY: - PB: outstanding growth (x2 PAT) on the back of NII and strong commercial activity (net new money of €8.7bn; customers +10%) - SAM: solid growth in net sales (€6.4bn), gaining market share in key markets - Insurance: continued growth backed by non-related and savings products. Gross fees increased 6% YoY Total fees Profit RoTE AuMs Total fees2 RoTE €1,704mn +15% €2,680mn +22% 28% +4pp €447bn +12% €2,776mn +1% 92% +36pp • Strong performance of the US franchise with relentless focus on the execution of our growth strategy • Double-digit revenue growth YoY across regions and businesses with fees increasing 15% and strong network collaboration revenue (+27% YoY) • SCIB maintains best-in-class efficiency and capital profitability levels, with profit growing 22% and RoTE increasing 4pp YoY to 28%. SCIB contributes 29% to Group’s profit Underlying P&L* Q3'23 % Q2'23 9M'23 % 9M'22 % 9M'22¹ Total revenue 2,126 3.0 6,479 20.8 16.2 Net operating income 1,262 -3.3 4,105 22.3 16.3 Attributable profit 804 -3.4 2,680 21.7 13.6 (*) € mn and % change in constant euros. (1) % change in current euros. Underlying P&L* Q3'23 % Q2'23 9M'23 % 9M'22 % 9M'22¹ Total revenue 874 0.0 2,591 39.0 37.8 Net operating income 590 -0.7 1,746 59.0 57.6 Attributable profit 432 -0.9 1,251 62.1 61.0 Contribution to profit 854 -0.8 2,486 26.4 26.4 (*) € mn and % change in constant euros. (1) % change in current euros.

41 6.8% 19.6% 9M'22 9M'23 668 820 9M'22 9M'23 Note: 9M'23 and YoY changes in constant euros. Cards does not include Digital Consumer Bank or PagoNxt. PagoNxt • Merchant Acquiring: strong TPV growth (+24% YoY) with market share gains in core markets • Payments Hub already one of the largest processors of A2A payments in Europe • Revenue increased 23% in constant euros due to overall increase in business activity and volumes across geographic segments especially in our Merchant (Getnet) and Trade businesses Financial performance +23% Merchant €149bn +24% Total Payments Volume (TPV) Number of transactions +32% Revenue EBITDA margin +13 pp Cards • 98 million cards, best quarter of the last six in portfolio growth underpinned by all regions • Best quarter in customer activity (€83bn turnover, +11% vs. Q3’22) • Revenue grew +10% in constant euros • High profitability with RoTE of 42% Cards €240bn +10% Fees +19% Turnover Revenue performance Constant € mn +10% 9M’22 vs. 9M’23 2,887 3,180 9M'22 9M'23

42 Appendix Investor Day Targets summary and our last step towards ONE SANTANDER Primary and Secondary segments Reconciliation of underlying results to statutory results Glossary

43 Reconciliation of underlying results to statutory results (1) Includes exchange differences. Explanation of January-September 2023 adjustments: • Temporary levy on revenue in Spain in the first quarter, totalling EUR 224 million, which was moved from total income to other gains (losses) and provisions. • Provisions to strengthen the balance sheet in Brazil in the first quarter, totalling EUR 235 million, net of tax and non-controlling interests (EUR 474 million recorded in net loan-loss provisions, EUR 213 million positive impact in tax and EUR 26 million in non-controlling interests). Explanation of January-September 2022 adjustments: • Mainly, payment holidays in Poland. Statutory results Adjustments Underlying results Statutory results Adjustments Underlying results Net interest income 32,139 — 32,139 28,460 — 28,460 Net fee income 9,222 — 9,222 8,867 — 8,867 Gains (losses) on financial transactions 1 1,969 — 1,969 1,115 — 1,115 Other operating income (459) 224 (235) 152 35 187 Total income 42,871 224 43,095 38,594 35 38,629 Administrative expenses and amortizations (18,961) — (18,961) (17,595) — (17,595) Net operating income 23,910 224 24,134 20,999 35 21,034 Net loan-loss provisions (9,511) 474 (9,037) (7,778) 287 (7,491) Other gains (losses) and provisions (1,862) (459) (2,321) (1,460) (322) (1,782) Profit before tax 12,537 239 12,776 11,761 — 11,761 Tax on profit (3,552) (213) (3,765) (3,538) — (3,538) Profit from continuing operations 8,985 26 9,011 8,223 — 8,223 Net profit from discontinued operations — — — — — — Consolidated profit 8,985 26 9,011 8,223 — 8,223 Non-controlling interests (842) (26) (868) (907) — (907) Profit attributable to the parent 8,143 — 8,143 7,316 — 7,316 January-September 2022January-September 2023

44 Appendix Investor Day Targets summary and our last step towards ONE SANTANDER Primary and Secondary segments Reconciliation of underlying results to statutory results Glossary

45 Glossary - Acronyms • ALCO: Assets and Liabilities Committee • AM: Asset management • AT1: Additional Tier 1 • AuMs: Assets under Management • BFG: Deposit Guarantee Fund in Poland • bn: Billion • BNPL: Buy now, pay later • bps: Basis points • c.: Circa • CAL: Customer assets and liabilities • CET1: Common equity tier 1 • CHF: Swiss franc • CIB: Corporate & Investment Bank • CoE: Cost of equity • CoR: Cost of risk • Covid-19: Coronavirus Disease 19 • CRE: Commercial Real Estate • DCB: Digital Consumer Bank • DGF: Deposit guarantee fund • DPS: Dividend per share • eNPS: Employee net promoter score • EPS: Earning per share • ESG: Environmental, social and governance • FL: Fully-loaded • FX: Foreign exchange • FY: Full year • GDF: Global Debt Finance • GDP: Gross domestic product • GTB: Global Transaction Banking • GWPs: Gross written premiums • HQLA: High quality liquid asset • HTC&S: Held to collect and sell • IFRS 9: International Financial Reporting Standard 9, regarding financial instruments • IPS: Institutional Protection Scheme • LCR: Liquidity coverage ratio • LLPs: Loan-loss provisions • LTV: Loan to value • M/LT: Medium-and long-term • mn: million • MREL: Minimum requirement for own funds and eligible liabilities • NII: Net interest income • NIM: Net interest margin • NOI: Net operating income • NPL: Non-performing loans • NPS: Net promoter score • OEM: Original equipment manufacturer • PB: Private Banking • PBT: Profit before tax • P&L: Profit and loss • PoS: Point of Sale • pp: Percentage points • Ps: Per share • QoQ: Quarter-on-Quarter • Repos: Repurchase agreements • RoA: Return on assets • RoE: Return on equity • RoRWA: Return on risk-weighted assets • RoTE: Return on tangible equity • RWA: Risk-weighted assets • SAM: Santander Asset Management • SAN: Santander • SBB: share buybacks • SCIB: Santander Corporate & Investment Banking • SC USA: Santander Consumer USA • SME: Small and Medium Enterprises • SRF: Single Resolution Fund • ST: Short term • T1/T2: Tier 1/Tier 2 • TLAC: Total loss-absorbing capacity • TLTRO: Targeted longer-term refinancing operations • TNAV: Tangible net asset value • TPV: Total Payments Volume • YoY: Year-on-Year • YTD: Year to date • WM&I: Wealth Management & Insurance

46 Glossary - Definitions Notes: The averages for the RoTE and RoRWA denominators are calculated using the monthly average over the period, which we believe should not differ materially from using daily balances. The risk-weighted assets included in the denominator of the RoRWA metric are calculated in line with the criteria laid out in the CRR (Capital Requirements Regulation). PROFITABILITY AND EFFICIENCY • RoTE: Return on tangible capital: Group attributable profit / average of: net equity (excluding minority interests) – intangible assets (including goodwill) • RoRWA: Return on risk-weighted assets: consolidated profit / average risk-weighted assets • Efficiency: Operating expenses / total income. Operating expenses defined as general administrative expenses + amortisations VOLUMES • Loans: Gross loans and advances to customers (excl. reverse repos) • Customer funds: Customer deposits excluding repos + marketed mutual funds CREDIT RISK • NPL ratio: Credit impaired loans and advances to customers, customer guarantees and customer commitments granted / Total risk. Total risk is defined as: Total loans and advances and guarantees to customers (including credit impaired assets) + contingent liabilities granted that are credit impaired • NPL coverage ratio: Total allowances to cover impairment losses on loans and advances to customers, customer guarantees and customer commitments granted / Credit impaired loans and advances to customers, customer guarantees and customer commitments granted • Cost of risk: Provisions to cover losses due to impairment of loans in the last 12 months / average customer loans and advances of the last 12 months CAPITALIZATION • Tangible net asset value per share – TNAVps: Tangible stockholders' equity / number of shares (excluding treasury shares). Tangible stockholders' equity calculated as shareholders equity + accumulated other comprehensive income - intangible assets ESG METRICS • Green Finance raised and facilitated = Nominal amount of PF, PF Advisory, PF bonds, Green bonds, ECA, M&A, ECM transactions classified by SCFS panel and reported in the League Tables since the beginning of the exercise. • SRI = Volume of assets under management classified as article 8 - promoting ESG objectives - and 9 - with explicit sustainability objectives - of the SFDR regulation (EU Reg. 2019/2088). Includes assets managed by Santander Asset Management (SAM), third-party funds and SAM funds managed with equivalent criteria in those geographies where SFDR does not apply (mainly LatAm). • Financial inclusion (# People) = Number of people who are unbanked, underbanked, in financial difficulty, with difficulties in accessing credit or with limited financial literacy who, through the Group's products, services and social investment initiatives, are able to access the financial system, receive tailored finance. Financially underserved groups are defined as people who do not have a current account, or who have an account but obtained alternative (non-bank) financial services in the last 12 months. Beneficiaries of various programs are included in the quantification process only once in the entire period. Only new empowered people are counted, taking as a base year those existing since 2019.

Thank You. Our purpose is to help people and businesses prosper. Our culture is based on believing that everything we do should be:

SIGNATURE Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized. Banco Santander, S.A. Date:    25 October 2023 By: /s/ José García Cantera Name: José García Cantera Title: Chief Financial Officer