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SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

Report of Foreign Issuer

Pursuant to Rule 13a-16 or 15d-16 of

the Securities Exchange Act of 1934

For the month of February, 2015

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  x            Form 40-F  ¨

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):

Yes  ¨            No   x

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):

Yes  ¨            No    x

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Banco Santander, S.A.

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INCORPORATION BY REFERENCE

Items 2 and 3 of this report on Form 6-K shall be deemed to be incorporated by reference into the registration statement on Form F-3 (Registration Number: 333-185153) of Banco Santander, S.A. and to be a part thereof from the date on which this report is filed, to the extent not superseded by documents or reports subsequently filed or furnished.

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Item 1

PRESS RELEASE

RESULTS 2014

Santander grows business in all markets

and makes a profit of EUR 5.816 billion in 2014

Ana Botín, Group Executive Chairman Banco Santander

Comunicación Externa.		1
Ciudad Grupo Santander Edificio Arrecife Pl. 2
28660 Boadilla del Monte (Madrid) Telf.: 34 91 289 52 11
email: [email protected]

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Madrid, February 3, 2015. Banco Santander made an attributable profit of EUR 5.816 billion, a 39% increase over 2013. For the first time since the start of the global economic crisis, gross profit increased in the ten main markets where the Group operates.

Results

The improvement in earnings is a consequence of the increase in basic revenues of 3%, a decrease in costs of almost 1% and a drop of 14% in loan-loss provisions compared to those registered in 2013. This is in a context of business growth, both in loans and customer funds, a falling non-performing loan ratio, an increase in the coverage rate and an improvement in the solvency ratio.

2014 results are set against a context of uneven slowdowns in Latin American economies, doubts about the Euro zone’s recovery that led the ECB to cut interest rates to historic lows of 0.05%, and favourable growth expectations in the U.K. and the U.S., although interest rates for both the pound and the dollar continued at unprecedented low levels.

The P&L account starts with an increase in basic revenues (interest income and fees) of 3%. The decrease in results from financial transactions, which are more volatile, generated a 2% increase in gross income, which reached EUR 42,612 million.

Cost reductions of almost 1% allowed net operating income to grow 4%, to EUR 22,574 million. This improvement in revenue and costs allowed the efficiency ratio to stand at 47%, which means a 1.1 percentage point reduction over 2013 and positions Banco Santander among the institutions with the best efficiency ratio.

Comunicación Externa.		2
Ciudad Grupo Santander Edificio Arrecife Pl. 2
28660 Boadilla del Monte (Madrid) Telf.: 34 91 289 52 11
email: [email protected]

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Loan loss provisions dropped 14%, to EUR 10,562 million, with decreases in key markets of 46% in the U.K., 28% in Spain and 18% in Brazil. Loan loss provisions were much lower than those made in 2012 but still higher than the average for the cycle.

The improvement in net operating income and the decrease in provisions allowed attributable profit to grow 39%, to EUR 5,816 million, allowing earnings per share to grow 24% compared to 2013, to EUR 0.48.

These results do not include net capital gains obtained from the sale of 85% of Altamira (EUR 385 million), the flotation of Santander Consumer USA (EUR 730 million), Santander Consumer Finance’s insurance partnership (EUR 250 million), nor the EUR 224 million registered in the U.K. for the change to pension commitments agreed in the first semester. These capital gains of EUR 1,589 million do not impact profit, since they have been set aside to cover costs of restructure, amortisation of intangibles and other write-downs.

Emerging economies (Latin America and Poland) accounted for 44% of profit and mature markets the rest (56%). By country, the largest contributors were the U.K. and Brazil, each with 19%, followed by Spain (14%), the U.S. (10%), Mexico (8%), Chile and Poland (6% each), Germany (5%), Argentina (4%) and Portugal (2%).

Balance sheet

Banco Santander closed 2014 with total assets of EUR 1.27 trillion, 12% more than 2013. The balance sheet is well balanced, with a loan portfolio equal to 113% of deposits, which gives the bank a very comfortable liquidity position. Before the crisis the ratio was 150%.

Comunicación Externa.		3
Ciudad Grupo Santander Edificio Arrecife Pl. 2
28660 Boadilla del Monte (Madrid) Telf.: 34 91 289 52 11
email: [email protected]

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At the close of 2014, the loan portfolio was EUR 761,928 million, up 5% from December of 2013, which means loans increased EUR 50,500 million for the year. Of the ten key markets where the Group operates, credit grew in all, except Portugal.

In Spain, the overall loan portfolio reached EUR 162,377 million, with an increase of 2% compared to the close of 2013, excluding temporary asset acquisitions. This growth is due to the increase in financing to companies, which grew 5%. The new mortgage production is growing strongly at 64%, but this does not compensate the amortizations produced for the year.

In the U.K., the loan portfolio was EUR 250,094 million, with growth of 3% over the close of 2013. Growth in corporate loans was especially strong at 8% year-on-year to EUR 30,700 million euros.

On the resource side, Grupo Santander’s deposits and mutual funds totaled EUR 772,336 million, with growth of 6%, equivalent to a gain of EUR 60,500 million for 2014. Deposits reached EUR 647,628 million and mutual funds EUR 124,708 million, with growth for the year of 7% and 20%, respectively. All markets captured new customer funds.

Current accounts, which make up more than half of total deposits, performed well in the Group’s ten core markets. Current accounts totaled EUR 362,201 million at the close of 2014, with growth of 18% compared to 2013. In twelve months, EUR 56,518 million in current accounts was captured. Current accounts represent a core product in the bank’s strategy of increasing customer loyalty, since most transactions are carried out through these accounts that centralize income and expenses.

Comunicación Externa.		4
Ciudad Grupo Santander Edificio Arrecife Pl. 2
28660 Boadilla del Monte (Madrid) Telf.: 34 91 289 52 11
email: [email protected]

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In Spain, customer funds (deposits and mutual funds) totaled EUR 217,109 million at the close of 2014, an increase of 5% for the year. Deposits remained stable, while assets under management in mutual funds grew 28%.

In the U.K., the volume of deposits and mutual funds increased to EUR 206,025 million and grew 2% for the year. The improvement is centered on growth in current accounts, which increased by EUR 19,300 million in twelve months, up 47%.

The Group’s NPL ratio decreased for the fourth quarter in a row, to 5.19%, 0.42 percentage points less than the end of 2013. At the same time, the provision coverage ratio improved by two points, to 67%.

The NPL ratio dropped for the second quarter in a row in the Group’s three main markets. The largest decrease was registered in Brazil, where it was down 0.59 points in the fourth quarter, to 5.05%. In Spain, it decreased 0.19 points in the last quarter of the year, to 7.38%. In the U.K., the NPL ratio continues at low levels, 1.79%, 0.01 point less than in the third quarter and 0.19 points below the close of 2013.

Comunicación Externa.		5
Ciudad Grupo Santander Edificio Arrecife Pl. 2
28660 Boadilla del Monte (Madrid) Telf.: 34 91 289 52 11
email: [email protected]

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Capital

With regards to capital ratios, Banco Santander’s computable capital stood at EUR 91,664 million at the end of the year, EUR 7,185 million more than a year earlier. On January 8, 2015, Santander raised capital by EUR 7,500 million through an accelerated bookbuilding offer to institutional investors. After this capital increase, the bank’s computable capital stood at EUR 99,164 million. The capital ratio was 11.8% and core capital, 9.7%, both “fully loaded”.

Along with the capital increase, the bank’s board of directors made public its new dividend policy against 2015 results. This consists of four payments of EUR 0.05 per share, of which three will be in cash and the fourth as a scrip dividend or cash, at the shareholders’ choice.

Banco Santander has a market capitalisation of around EUR 85,000 million, which makes it the leading bank in the Euro zone and tenth largest in the world. It has 3,240,395 shareholders and 185,405 employees serving more than 100 million customers through 12,951 branches.

More information at www.santander.com

Comunicación Externa.		6
Ciudad Grupo Santander Edificio Arrecife Pl. 2
28660 Boadilla del Monte (Madrid) Telf.: 34 91 289 52 11
email: [email protected]

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Preliminary note:

In order to facilitate the following comparative analysis, the 2013 financial information has been re-expressed (not audited), as set out on page 15 of this report. The changes were due, on the one hand, to the early adoption of IFRIC 21 on levies, which gave rise to a change in the recognition of the contributions made by Santander UK to the Financial Services Compensation Scheme and of the contributions made by the Group’s Spanish financial institutions to the Deposit Guarantee Fund. And on the other, to taking control of Santander Consumer USA, in 2014, and the loss of control of the fund management companies in 2013, as if they had been effective in the previously presented periods.

Non recurring capital gains and provisions are shown separately as “net capital gains and provisions”.

KEY CONSOLIDATED DATA

(*).- Variations w/o exchange rate:

Quarterly: Net interest income: +3.7%; Gross income: +1.1%; Pre-provision profit: -0.7%; Attributable profit: -9.3%

Year-on-year: Net interest income: +8.8%; Gross income: +6.2%; Pre-provision profit: +9.1%; Attributable profit: +49.3%

RoTE: Group attributable profit / (Average of capital + reserves + retained profit + valuation adjustments—goodwill—other intangible assets). In 2014, pro-forma taking into account the January 2015 capital increase

JANUARY - DECEMBER

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Item 2

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Preliminary note:

In order to facilitate the following comparative analysis, the 2013 financial information has been re-expressed (not audited), as set out on page 15 of this report. The changes were due, on the one hand, to the early adoption of IFRIC 21 on levies, which gave rise to a change in the recognition of the contributions made by Santander UK to the Financial Services Compensation Scheme and of the contributions made by the Group’s Spanish financial institutions to the Deposit Guarantee Fund. And on the other, to taking control of Santander Consumer USA, in 2014, and the loss of control of the fund management companies in 2013, as if they had been effective in the previously presented periods.

Non recurring capital gains and provisions are shown separately as “net capital gains and provisions”.

KEY CONSOLIDATED DATA

(*).- Variations w/o exchange rate:

Quarterly: Net interest income: +3.7%; Gross income: +1.1%; Pre-provision profit: -0.7%; Attributable profit: -9.3%

Year-on-year: Net interest income: +8.8%; Gross income: +6.2%; Pre-provision profit: +9.1%; Attributable profit: +49.3%

RoTE: Group attributable profit / (Average of capital + reserves + retained profit + valuation adjustments—goodwill—other intangible assets). In 2014, pro-forma taking into account the January 2015 capital increase

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FINANCIAL REPORT 2014 CONSOLIDATED FINANCIAL INFORMATION

n INCOME STATEMENT (EUR Million)

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CONSOLIDATED FINANCIAL INFORMATION FINANCIAL REPORT 2014

n QUARTERLY INCOME STATEMENT (EUR Million)

n EXCHANGE RATES: 1 EURO / CURRENCY PARITY

JANUARY - DECEMBER				5

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FINANCIAL REPORT 2014 CONSOLIDATED FINANCIAL INFORMATION

n NET FEES

    EUR Million

n OPERATING EXPENSES

    EUR Million

6				JANUARY - DECEMBER

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CONSOLIDATED FINANCIAL INFORMATION FINANCIAL REPORT 2014

n OPERATING MEANS

    EUR Million

n NET LOAN-LOSS PROVISIONS

    EUR Million