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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 6-K/A

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of March 2018

Commission File Number: 000-53445

KB Financial Group Inc.

(Translation of registrant’s name into English)

26, Gukjegeumyung-ro 8-gil, Yeongdeungpo-gu, Seoul 07331, Korea

(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  ☐

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):  ☐

Note: Regulation S-T Rule 101(b)(1) only permits the submission in paper of a Form 6-K if submitted solely to provide an attached annual report to security holders.

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):  ☐

Note: Regulation S-T Rule 101(b)(7) only permits the submission in paper of a Form 6-K if submitted to furnish a report or other document that the registrant foreign private issuer must furnish and make public under the laws of the jurisdiction in which the registrant is incorporated, domiciled or legally organized (the registrant’s “home country”), or under the rules of the home country exchange on which the registrant’s securities are traded, as long as the report or other document is not a press release, is not required to be and has not been distributed to the registrant’s security holders, and, if discussing a material event, has already been the subject of a Form 6-K submission or other Commission filing on EDGAR.

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EXPLANATORY NOTE

This Report of Foreign Private Issuer on Form 6-K/A (this “Amended Report”) is furnished to amend the Report of Foreign Private Issuer on Form 6-K furnished to the Securities and Exchange Commission on March 13, 2018 under the title “Audit Report of KB Financial Group Inc. for Fiscal Year 2017” (the “Original Report”). This Amended Report amends certain notes included in the English-language translation of the Consolidated Audit Report of KB Financial Group for fiscal year 2017 (the “Consolidated Audit Report”) attached as Exhibit 99.1 to the Original Report.

The amendments consist of: (i) the amount of the line item “Mortgage loans” and the total assets pledged as collateral for 2017 under Note 8 (Assets pledged as collateral) and (ii) the amounts of the line items “Written-off,” “Recoveries from written-off loans,” “Sale and repurchase” and “Other changes” for 2017 under Note 11 (Allowances for Loan Losses).

The English-language translation of the amended Consolidated Audit Report reflecting the above revisions is attached as Exhibit 99.1 to this Amended Report. The amended Notes 8 and 11 are set forth below.

8. Assets pledged as collateral

Details of assets pledged as collateral as of December 31, 2017 and 2016, are as follows:

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11. Allowances for Loan Losses

Changes in the allowances for loan losses for the years ended December 31, 2017 and 2016, are as follows:

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SIGNATURES

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.

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Exhibit 99.1

KB Financial Group Inc. and Subsidiaries

Consolidated Financial Statements

December 31, 2017 and 2016

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KB Financial Group Inc. and Subsidiaries

Index

December 31, 2017 and 2016

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Independent Auditor’s Report

(English Translation of a Report Originally Issued in Korean)

To the Shareholders and Board of Directors of KB Financial Group Inc.

We have audited the accompanying consolidated financial statements of KB Financial Group Inc. and its subsidiaries (collectively referred to as the “Group”), which comprise the consolidated statements of financial position as of December 31, 2017 and 2016, and the consolidated statements of comprehensive income, consolidated statements of changes in equity and consolidated statements of cash flows for the years then ended, and notes to the consolidated financial statements, including a summary of significant accounting policies and other explanatory information.

Management’s Responsibility for the Financial Statements

Management is responsible for the preparation and fair presentation of the consolidated financial statements in accordance with International Financial Reporting Standards as adopted by the Republic of Korea (Korean IFRS), and for such internal control as management determines is necessary to enable the preparation of financial statements that are free from material misstatement, whether due to fraud or error.

Auditor’s Responsibility

Our responsibility is to express an opinion on the consolidated financial statements based on our audits. We conducted our audits in accordance with Korean Standards on Auditing. Those standards require that we comply with ethical requirements, and plan and perform the audit to obtain reasonable assurance about whether the consolidated financial statements are free from material misstatement.

An audit involves performing procedures to obtain audit evidence about the amounts and disclosures in the consolidated financial statements. The procedures selected depend on our judgment, including the assessment of the risks of material misstatement of the consolidated financial statements, whether due to fraud or error. In making those risk assessments, we consider internal control relevant to the Group’s preparation and fair presentation of the consolidated financial statements in order to design audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Group’s internal control. Accordingly, we express no such opinion. An audit also includes evaluating the appropriateness of accounting policies used and the reasonableness of significant accounting estimates made by management, as well as evaluating the overall presentation of the consolidated financial statements.

We believe that the audit evidence we have obtained is sufficient and appropriate to provide a basis for our opinion.

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Opinion

In our opinion, the accompanying consolidated financial statements present fairly, in all material respects, the consolidated financial position of the Group as of December 31, 2017 and 2016, and its consolidated financial performance and its consolidated cash flows for the years then ended in accordance with Korean IFRS.

Auditing standards and their application in practice vary among countries. The procedures and practices used in the Republic of Korea to audit such financial statements may differ from those generally accepted and applied in other countries.

/s/ Samil PricewaterhouseCoopers

Seoul, Korea

March 12, 2018

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KB Financial Group Inc. and Subsidiaries

Consolidated Statements of Financial Position

December 31, 2017 and 2016

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KB Financial Group Inc. and Subsidiaries

Consolidated Statements of Comprehensive Income

Years Ended December 31, 2017 and 2016

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KB Financial Group Inc. and Subsidiaries

Consolidated Statements of Changes in Equity

Years Ended December 31, 2017 and 2016

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KB Financial Group Inc. and Subsidiaries

Consolidated Statements of Cash Flows

Years Ended December 31, 2017 and 2016

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KB Financial Group Inc. and Subsidiaries

Notes to the Consolidated Financial Statements

December 31, 2017 and 2016

1. The Parent Company

KB Financial Group Inc. (the Parent Company) was incorporated on September 29, 2008, under the Financial Holding Companies Act of Korea. KB Financial Group Inc. and its subsidiaries (the “Group”) derive substantially all of their revenue and income from providing a broad range of banking and related financial services to consumers and corporations primarily in Korea and in selected international markets. The Parent Company’s principal business includes ownership and management of subsidiaries and associated companies that are engaged in financial services or activities. In 2011, Kookmin Bank spun off its credit card business segment and established a new separate credit card company, KB Kookmin Card Co., Ltd., and KB Investment & Securities Co., Ltd. merged with KB Futures Co., Ltd. The Group established KB Savings Bank Co., Ltd. in January 2012, acquired Yehansoul Savings Bank Co., Ltd. in September 2013, and KB Savings Bank Co., Ltd. merged with Yehansoul Savings Bank Co., Ltd. in January 2014. In March 2014, the Group acquired Woori Financial Co., Ltd. and changed the name to KB Capital Co., Ltd. Meanwhile, the Group included LIG Insurance Co., Ltd. as an associate and changed the name to KB Insurance Co., Ltd. in June 2015. Also, the Group included Hyundai Securities Co., Ltd. as an associate in June 2016 and included as a subsidiary in October 2016 by comprehensive exchange of shares. Hyundai Securities Co., Ltd. merged with KB Investment&Securities Co., Ltd. in December 2016 and changed the name to KB Securities Co., Ltd. in January 2017. KB Insurance Co., Ltd. became one of the subsidiaries through a tender offer in May 2017. KB Insurance Co., Ltd. became one of the subsidiaries through a tender offer in May 2017.

The Parent Company’s share capital as of December 31, 2017, is W2,090,558 million. The Parent Company has been listed on the Korea Exchange (“KRX”) since October 10, 2008, and on the New York Stock Exchange (“NYSE”) for its American Depositary Shares (“ADS”) since September 29, 2008. Number of shares authorized in its Articles of Incorporation is 1,000 million.

2. Basis of Preparation

2.1 Application of Korean IFRS

The Group maintains its accounting records in Korean won and prepares statutory financial statements in the Korean language (Hangul) in accordance with International Financial Reporting Standards as adopted by the Republic of Korea (Korean IFRS). The accompanying consolidated financial statements have been condensed, restructured and translated into English from the Korean language financial statements.

Certain information attached to the Korean language financial statements, but not required for a fair presentation of the Group’s financial position, financial performance or cash flows, is not presented in the accompanying consolidated financial statements.

The consolidated financial statements of the Group have been prepared in accordance with Korean IFRS. These are the standards, subsequent amendments and related interpretations issued by the International Accounting Standards Board (“IASB”) that have been adopted by the Republic of Korea.

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KB Financial Group Inc. and Subsidiaries

Notes to the Consolidated Financial Statements

December 31, 2017 and 2016

The preparation of consolidated financial statements requires the use of certain critical accounting estimates. Management also needs to exercise judgment in applying the Group’s accounting policies. The areas involving a higher degree of judgment or complexity, or areas where assumptions and estimates are significant to the consolidated financial statements are disclosed in Note 2.4.

The Group has applied the following standards and amendments for the first time for their annual reporting period commencing January 1, 2017. The adoption of these amendments did not have any impact on the current period or any prior period and is not likely to affect future periods.

Amendments to Korean IFRS 1007 Statement of Cash flows requires to provide disclosures that enable users of financial statements to evaluate changes in liabilities arising from financing activities, including both changes arising from cash flows and non-cash flows.

Amendments to Korean IFRS 1012 clarify how to account for deferred tax assets related to debt instruments measured at fair value. Korean IFRS 1012 provides requirements on the recognition and measurement of current or deferred tax liabilities or assets. The amendments issued clarify the requirements on recognition of deferred tax assets for unrealized losses, to address diversity in practice.

Amendments to Korean IFRS 1112 clarify when an entity’s interest in a subsidiary, a joint venture or an associate is classified as held for sales in accordance with Korean IFRS 1105, the entity is required to disclose other information except for summarized financial information in accordance with Korean IFRS 1112.

Certain new accounting standards and interpretations that have been published that are not mandatory for annual reporting period commencing January 1, 2017 and have not been early adopted by the Group are set out below.

When an investment in an associate or a joint venture is held by, or it held indirectly through, an entity that is a venture capital organization, or a mutual fund, unit trust and similar entities including investment-linked insurance funds, the entity may elect to measure that investment at fair value through profit or loss in accordance with Korean IFRS 1109. The amendments clarify that an entity shall make this election separately for each associate of joint venture, at initial recognition of the associate or joint venture. The Group will apply these amendments retrospectively for annual periods beginning on or after January 1, 2018, and early adoption is permitted. The Group does not expect the amendments to have a significant impact on the consolidated financial statements because the Group is not a venture capital organization.

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KB Financial Group Inc. and Subsidiaries

Notes to the Consolidated Financial Statements

December 31, 2017 and 2016

Paragraph 57 of Korean IFRS 1040 clarifies that a transfer to, or from, investment property, including Property under construction, can only be made if there has been a change in use that is supported by Evidence, and provides a list of circumstances as examples. The amendment will be effective for annual periods beginning on or after January 1, 2018. With early adoption permitted. The Group does not expect the amendment to have a significant impact on the financial statements.

Amendments to Korean IFRS 1102 clarify accounting for a modification to the terms and conditions of a share-based payment that changes the classification of the transaction from cash-settled to equity-settled. Amendments also clarify that the measurement approach should treat the terms and conditions of a cash-settled award in the same way as for an equity-settled award. The amendments will be effective for annual periods beginning on or after January 1, 2018, with early adoption. The Group does not expect the amendments to have a significant impact on the consolidated financial statements.

According to these enactments, the date of the transaction for the purpose of determining the exchange rate to use on initial recognition of the related asset, expense or income (or part of it) is the date on which an entity initially recognizes the non-monetary asset or non-monetary liability arising from the payment or receipt of advance consideration. If there are multiple payments or receipts in advance, the entity shall determine a date of the transaction for each payment or receipt of advance consideration. These enactments will be effective for annual periods beginning on or after January 1, 2018, with early adoption permitted. The Group does not expect the enactments to have a significant impact on the consolidated financial statements.

The new standard for financial instruments issued on September 25, 2015 is effective for annual periods beginning on or after January 1, 2018 with early application permitted. This standard will replace Korean IFRS 1039 Financial Instruments: Recognition and Measurement. The Group will apply the standards for annual periods beginning on or after January 1, 2018.

The standard requires retrospective application with some exceptions. For example, an entity is not required to restate prior periods in relation to classification, measurement and impairment of financial instruments. The standard requires prospective application of its hedge accounting requirements for all hedging relationships except the accounting for time value of options and other exceptions.

Korean IFRS 1109 Financial Instruments requires all financial assets to be classified and measured on the basis of the entity’s business model for managing financial assets and the contractual cash flow characteristics of the financial assets. A new impairment model, an expected credit loss model, is introduced and any subsequent changes in expected credit losses will be recognized in profit or loss. Also, hedge accounting rules amended to extend the hedging relationship, which consists only of eligible hedging instruments and hedged items, qualifies for hedge accounting.

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KB Financial Group Inc. and Subsidiaries

Notes to the Consolidated Financial Statements

December 31, 2017 and 2016

An effective implementation of Korean IFRS 1109 requires preparation processes including financial impact assessment, accounting policy establishment, accounting system development and the system stabilization. The impact on the Group’s financial statements due to the application of the standard is dependent on judgements made in applying the standard, financial instruments held by the Group and macroeconomic variables.

Within the Group, Korean IFRS 1109 Task Force Team (‘TFT’) has been set up to prepare for implementation of Korean IFRS 1109 since October 2015. There are three stages for implementation of Korean IFRS, such as analysis, design and implementation, and preparation for application. The Group analyzed the financial impacts of Korean IFRS 1109 on its consolidated financial statements.

The Group performed an impact assessment to identify potential financial effects of applying Korean IFRS 1109. The assessment was performed based on available information as at December 31, 2017, and the results of the assessment are explained as below. The results of the assessment in the financial effects as at December 31, 2017 may change due to additional information and decisions that the Group may obtain in the future.

(a) Classification and Measurement of Financial Assets

When implementing Korean IFRS 1109, the classification of financial assets will be driven by the Group’s business model for managing the financial assets and contractual terms of cash flow. The following table shows the classification of financial assets measured subsequently at amortized cost, at fair value through other comprehensive income and at fair value through profit or loss. For hybrid (combined) instruments, the Group does not measure an embedded derivative separately from its host contract, financial assets with embedded derivatives are classified in their entirety.

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KB Financial Group Inc. and Subsidiaries

Notes to the Consolidated Financial Statements

December 31, 2017 and 2016

With the implementation of Korean IFRS 1109, the criteria to classify the financial assets at amortized cost or at fair value through other comprehensive income are more strictly applied than the criteria applied with Korean IFRS 1039. Accordingly, the financial assets at fair value through profit or loss may increase by implementing Korean IFRS 1109 and may result an extended fluctuation in profit or loss.

The following table presents the impact of the change in classification and measurement of financial instrument (excluding derivatives) held by the Group as at December 31, 2017, using the financial instrument accounting system developed by the Group with applying Korean IFRS 1109.

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KB Financial Group Inc. and Subsidiaries

Notes to the Consolidated Financial Statements

December 31, 2017 and 2016

With the implementation of Korean IFRS 1109, as at December 31, 2017, W2,782,821 million of cash and due from financial institutions, W629,223 million of loans, W9,313,034 million of financial assets available-for-sales and W269,661 million of assets held-to-maturity are classified to financial assets recognize at fair value through profit or loss. These classifications will increase the financial assets recognized at fair value through profit or loss from 7.7% to 10.8% over the total financial assets (excluding derivatives) of W418,442,272 million and may result an extended fluctuation in profit or loss.

(b) Classification and Measurement of Financial Liabilities

Korean IFRS 1109 requires that the amount of the change of fair value attributable to changes in the credit risk in the financial liabilities designated at fair value through profit or loss will be recognized in other comprehensive income, not in profit or loss, unless this treatment of the credit risk component creates or enlarges a measurement mismatch. Amounts presented in other comprehensive income are not subsequently transferred to profit or loss.

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KB Financial Group Inc. and Subsidiaries

Notes to the Consolidated Financial Statements

December 31, 2017 and 2016

Under Korean IFRS 1039, all financial liabilities designated at fair value through profit or loss recognized their fair value change in profit or loss. However, under Korean IFRS 1109, certain fair value change will be recognized in other comprehensive income and as a result, profit or loss from fair value change may decrease. Based on results from the impact assessment, the amount of change in the fair value of the financial liabilities designated at fair value through profit or loss in applying Korean IFRS 1109 is W10,078,288 million and W10,438 million is attributable to changes in the credit risk of that liability.

(c) Impairment: Financial Assets and Contract Assets

The new impairment model requires the recognition of impairment provisions based on expected credit losses (ECL) rather than only incurred credit losses as is the case under Korean IFRS 1039. It applies to financial assets classified at amortized cost, debt instruments measured at fair value through other comprehensive income, lease receivables, contract assets, loan commitments and certain financial guarantee contracts.

Under Korean IFRS 1109, a credit event (or impairment ‘trigger’) no longer has to occur before credit losses are recognized. The Group will always recognize (at a minimum) 12-month expected credit losses in profit or loss. Lifetime expected losses will be recognized on assets for which there is a significant increase in credit risk after initial recognition.

Under Korean IFRS 1109, the asset that is credit-impaired at initial recognition would recognize all changes in lifetime expected credit losses since the initial recognition as a loss allowance.

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KB Financial Group Inc. and Subsidiaries

Notes to the Consolidated Financial Statements

December 31, 2017 and 2016

According to the financial assessment, the Group owns loss allowance set out below.

(d) Hedge Accounting

Hedge accounting mechanics (fair value hedges, cash flow hedges and hedge of net investments in a foreign operations) required by Korean IFRS 1039 remains unchanged in Korean IFRS 1109, however, the new hedge accounting rules will align the accounting for hedging instruments more closely with the Group’s risk management practices. As a general rule, more hedge relationships might be eligible for hedge accounting, as the standard introduces a more principles-based approach. Korean IFRS 1109 allows more hedging instruments and hedged items to qualify for hedge accounting, and relaxes the hedge accounting requirement by removing two hedge effectiveness tests that are a prospective test to ensure that the hedging relationship is expected to be highly effective and a quantitative retrospective test (within range of 80-125%) to ensure that the hedging relationship has been highly effective throughout the reporting period.

With implementation of Korean IFRS 1109, volatility in profit or loss may be reduced as some items that were not eligible as hedged items or hedging instruments under Korean IFRS 1039 are now eligible under Korean IFRS 1109.

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KB Financial Group Inc. and Subsidiaries

Notes to the Consolidated Financial Statements

December 31, 2017 and 2016

Furthermore, when the Group first applies Korean IFRS 1109, it may choose as its accounting policy to continue to apply all of the hedge accounting requirements of Korean IFRS 1039 instead of the requirements of Korean IFRS 1109.

Meanwhile, as at December 31,2017, the Group has not applied hedge accounting more for the risk management practices which can be applied hedge accounting by Korean IFRS 1109 but cannot be satisfied with hedge accounting requirements by Korean IFRS 1039.

Korean IFRS 1115 Revenue from Contracts with Customers issued on November 6, 2015 replaces Korean IFRS 1018 Revenue, Korean IFRS 1011 Construction Contracts, Interpretation 2031 Revenue-Barter Transactions Involving Advertising Services, Interpretation 2113 Customer Loyalty Programs, Interpretation 2115 Agreements for the Construction of Real Estate and Interpretation 2118 Transfers of assets from customers.

Korean IFRS 1018 and other, the current standard, provide revenue recognition criteria by type of transactions; such as, sales goods, the rendering of services, interest income, royalty income, dividend income, and construction contracts. However, Korean IFRS 1115, the new standard, is based on the principle that revenue is recognized when control of a good or service transfers to a customer – so the notion of control replaces the existing notion of risks and rewards.

A new five-step process must be applied before revenue from contract with customer can be recognized:

The Group will apply new standard for annual reporting periods beginning on or after January 1, 2018 and early adoption is permitted. The Group performed a preliminary impact assessment on the employees of the accounting department based on the current situation and available information as at December 31, 2017 to identify potential financial effects of applying Korean IFRS 1115. As a result, the Group does not expect that enactment of this statement will not have a significant impact on the consolidated financial statements. The results of the assessment as at December 31, 2017, may change due to additional information that the Group may obtain after the assessment.

Korean IFRS 1116 Leases issued on May 22, 2017 is effective for annual periods beginning on or after January 1, 2019, with early adoption permitted. This standard will replace Korean IFRS 1017 Leases, Interpretation 2104 Determining whether an Arrangement contains a Lease, Interpretation 2015 Operating Leases-Incentives, and Interpretation 2027 Evaluating the Substance of Transactions Involving the Legal Form of a Lease.

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KB Financial Group Inc. and Subsidiaries

Notes to the Consolidated Financial Statements

December 31, 2017 and 2016

At inception of a contract, the entity shall assess whether the contract is, or contains, a lease. Also, at the date of initial application, the entity shall assess whether the contract is, or contains, a lease in accordance with the standard. However, the entity will not need to reassess all contracts with applying the practical expedient because the entity elected to apply the practical expedient only to contracts entered before the date of initial application.

For a contract that is, or contains, a lease, the entity shall account for each lease component within the contract as a lease separately from non-lease components of the contract. A lease is required to recognize a right-of-use asset representing its right to use the underlying leased asset and a lease liability representing its obligation to make lease payments. The lessee may elect not to apply the requirements to short-term lease (a lease term of 12 months or less at the commencement date) and low value assets (e.g. underlying assets below $5,000). In addition, as a practical expedient, the lessee may elect, by class of underlying asset, not to separate non-lease components from lease components, and instead account for each lease component and any associated non-lease components as a single lease component.

The classification criteria between a financial lease and an operating lease for a lessor under Korean IFRS 1116 are similar to Korean IFRS 1017.

The Group is currently in progress of analyzing the potential impact on its consolidated financial statements resulting from the application of Korean IFRS 1116.

2.2 Measurement Basis

The consolidated financial statements have been prepared under the historical cost convention unless otherwise specified.

2.3 Functional and Presentation Currency

Items included in the financial statements of each entity of the Group are measured using the currency of the primary economic environment in which the entity operates (the “functional currency”). The consolidated financial statements are presented in Korean won, which is the Parent Company’s functional and presentation currency (Notes 3.2.1 and 3.2.2).

2.4 Critical Accounting Estimates

The preparation of consolidated financial statements requires the application of accounting policies, certain critical accounting estimates and assumptions that may have a significant impact on the assets (liabilities) and incomes (expenses). Management’s estimates of outcomes may differ from actual outcomes if management’s estimates and assumptions based on management’s best judgment at the reporting date are different from the actual environment.

Estimates and assumptions are continually evaluated and any change in an accounting estimate is recognized prospectively by including it in profit or loss in the period of the change, if the change affects that period only. Alternatively if the change in accounting estimate affects both the period of change and future periods, that change is recognized in the profit or loss of all those periods.

Uncertainty in estimates and assumptions with significant risk that may result in material adjustment to the consolidated financial statements are as follows:

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KB Financial Group Inc. and Subsidiaries

Notes to the Consolidated Financial Statements

December 31, 2017 and 2016

2.4.1 Income taxes

The Group is operating in numerous countries and the income generated from these operations is subject to income taxes based on tax laws and interpretations of tax authorities in numerous jurisdictions. There are many transactions and calculations for which the ultimate tax determination is uncertain. If certain portion of the taxable income is not used for investments, increase in wages, or dividends in accordance with the Tax System for Recirculation of Corporate Income, the Group is liable to pay additional income tax calculated based on the tax laws. The new tax system is effective for three years from 2015. Accordingly, the measurement of current and deferred income tax is affected by the tax effects from the new system. As the Group’s income tax is dependent on the investments, increase in wages and dividends, there exists uncertainty with regard to measuring the final tax effects.

2.4.2 Fair value of financial instruments

The fair value of financial instruments where no active market exists or where quoted prices are not otherwise available is determined by using valuation techniques. Financial instruments, which are not actively traded in the market and those with less transparent market prices, will have less objective fair values and require broad judgment on liquidity, concentration, uncertainty in market factors and assumptions in price determination and other risks.

As described in the significant accounting policies in Note 3.3, ‘Recognition and Measurement of Financial Instruments’, diverse valuation techniques are used to determine the fair value of financial instruments, from generally accepted market valuation models to internally developed valuation models that incorporate various types of assumptions and variables.

2.4.3 Provisions for credit losses (allowances for loan losses, provisions for acceptances and guarantees, and unused loan commitments)

The Group determines and recognizes allowances for losses on loans through impairment testing and recognizes provisions for guarantees, and unused loan commitments. The accuracy of provisions for credit losses is determined by the methodology and assumptions used for estimating expected cash flows of the borrower for individually assessed allowances of loans, collectively assessed allowances for groups of loans, guarantees and unused loan commitments.

2.4.4 Net defined benefit liability

The present value of net defined benefit liability depends on a number of factors that are determined on an actuarial basis using a number of assumptions (Note 24).

2.4.5 Impairment of goodwill

The recoverable amounts of cash-generating units have been determined based on value-in-use calculations to test whether goodwill has suffered any impairment (Note 15).

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KB Financial Group Inc. and Subsidiaries

Notes to the Consolidated Financial Statements

December 31, 2017 and 2016

3. Significant Accounting Policies

The significant accounting policies applied in the preparation of these consolidated financial statements are set out below. These policies have been consistently applied to all periods presented, unless otherwise stated.

3.1 Consolidation

3.1.1 Subsidiaries

Subsidiaries are companies that are controlled by the Group. The Group controls an investee when it is exposed, or has rights, to variable returns from its involvement with the investee and has the ability to affect those returns through its power over the investee. The existence and effects of potential voting rights that are currently exercisable or convertible are considered when assessing whether the Group controls another entity. Subsidiaries are fully consolidated from the date when control is transferred to the Group and de-consolidated from the date when control is lost.

If a subsidiary uses accounting policies other than those adopted in the consolidated financial statements for like transactions and events in similar circumstances, appropriate adjustments are made to make the subsidiary’s accounting policies conform to those of the Group when the subsidiary’s financial statements are used by the Group in preparing the consolidated financial statements.

Profit or loss and each component of other comprehensive income are attributed to the owners of the parent and to the non-controlling interests, if any. Total comprehensive income is attributed to the owners of the parent and to the non-controlling interests even if this results in the non-controlling interests having a deficit balance.

Transactions with non-controlling interests that do not result in loss of control are accounted for as equity transactions; that is, as transactions with the owners in their capacity as owners. The difference between fair value of any consideration paid and the relevant share acquired of the carrying value of net assets of the subsidiary is recorded in equity. Gains or losses on disposals to non-controlling interests are also recorded in equity.

When the Group ceases to have control, any retained interest in the entity is re-measured to its fair value at the date when control is lost, with the change in carrying amount recognized in profit or loss. The fair value is the initial carrying amount for the purposes of subsequently accounting for the retained interest as an associate, joint venture or financial asset. In addition, any amounts previously recognized in other comprehensive income in respect of that entity are accounted for as if the Group had directly disposed of the related assets or liabilities. This may mean that amounts previously recognized in other comprehensive income are reclassified to profit or loss.

The Group applies the acquisition method to account for business combinations. The consideration transferred is measured at the fair values of the assets transferred, and identifiable assets acquired and liabilities and contingent liabilities assumed in a business combination are initially measured at their fair values at the acquisition date. The Group recognizes any non-controlling interest in the acquiree on an acquisition-by-acquisition basis in the event of liquidation, either at fair value or at the non-controlling interest’s proportionate share of the recognized amounts of acquiree’s identifiable net assets. Acquisition-related costs are expensed as incurred.

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KB Financial Group Inc. and Subsidiaries

Notes to the Consolidated Financial Statements

December 31, 2017 and 2016

In a business combination achieved in stages, the Group shall remeasure its previously held equity interest in the acquiree at its acquisition-date fair value and recognize the resulting gain or loss, if any, in profit or loss or other comprehensive income, as appropriate. In prior reporting periods, the Group may have recognized changes in the value of its equity interest in the acquiree in other comprehensive income. If so, the amount that was recognised in other comprehensive income shall be recognised on the same basis as would be required if the Group had disposed directly of the previously held equity interest.

The Group applies the book amount method to account for business combinations of entities under a common control. Identifiable assets acquired and liabilities assumed in a business combination are measured at their book amounts on the consolidated financial statements of the Group. In addition, the difference between the sum of consolidated book amounts of the assets and liabilities transferred and accumulated other comprehensive income; and the consideration paid is recognized as capital surplus.

3.1.2 Associates and Joint ventures

Associates and joint ventures are entities over which the Group has significant influence in the financial and operating policy decisions. If the Group holds 20% or more of the voting power of the investee, it is presumed that the Group has significant influence.

Under the equity method, investments in associates and joint ventures are initially recognized at cost and the carrying amount is increased or decreased to recognize the Group’s share of the profit or loss of the investee and changes in the investee’s equity after the date of acquisition. The Group’s share of the profit or loss of the investee is recognized in the Group’s profit or loss. Distributions received from an investee reduce the carrying amount of the investment. Profit and loss resulting from ‘upstream’ and ‘downstream’ transactions between the Group and associates are eliminated to the extent at the Group’s interest in associates. Unrealized losses are eliminated in the same way as unrealized gains except that they are only eliminated to the extent that there is no evidence of impairment.

If associates and joint ventures use accounting policies other than those adopted in the consolidated financial statements for like transactions and events in similar circumstances, appropriate adjustments are made to make the associate’s accounting policies conform to those of the Group when the associate’s financial statements are used by the Group in applying equity method.

After the carrying amount of the investment is reduced to zero, additional losses are provided for, and a liability is recognized, only to the extent that the Group has incurred legal or constructive obligations or made payments on behalf of the investee.

The Group determines at each reporting period whether there is any objective evidence that the investments in the associates and joint ventures are impaired. If this is the case, the Group calculates the amount of impairment as the difference between the recoverable amount of the associates and its carrying value and recognizes the amount as ‘non-operating income (expense)’ in the statements of comprehensive income.

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December 31, 2017 and 2016

3.1.3 Structured entity

A structured entity is an entity that has been designed so that voting or similar rights are not the dominant factor in deciding who controls the entity. When the Group decides whether it has power to the structured entities in which the Group has interests, it considers factors such as the purpose, the form, the practical ability to direct the relevant activities of a structured entity, the nature of its relationship with a structured entity and the amount of exposure to variable returns.

3.1.4 Trusts and funds

The Group provides management services for trust assets, collective investment and other funds. These trusts and funds are not consolidated in the Group’s consolidated financial statements, except for trusts and funds over which the Group has control.

3.1.5 Intra-group transactions

All intra-group balances and transactions, and any unrealized gains arising on intra-group transactions, are eliminated in preparing the consolidated financial statements. Unrealized losses are eliminated in the same way as unrealized gains except that they are only eliminated to the extent that there is no evidence of impairment.

3.2 Foreign Currency

3.2.1 Foreign currency transactions

A foreign currency transaction is recorded, on initial recognition in the functional currency, by applying the spot exchange rate between the functional currency and the foreign currency at the date of the transaction. At the end of each reporting period, foreign currency monetary items are translated using the closing rate which is the spot exchange rate at the end of the reporting period. Non-monetary items that are measured at fair value in a foreign currency are translated using the spot exchange rates at the date when the fair value was determined and non-monetary items that are measured in terms of historical cost in a foreign currency are translated using the spot exchange rate at the date of the transaction.

Exchange differences arising on the settlement of monetary items or on translating monetary items at rates different from those at which they were translated on initial recognition during the period or in previous consolidated financial statements are recognized in profit or loss in the period in which they arise, except for exchange differences arising on net investments in a foreign operation and financial liability designated as a hedge of the net investment. When gains or losses on a non-monetary item are recognized in other comprehensive income, any exchange component of those gains or losses are also recognized in other comprehensive income. Conversely, when gains or losses on a non-monetary item are recognized in profit or loss, any exchange component of those gains or losses are also recognized in profit or loss.

3.2.2 Foreign operations

The financial performance and financial position of all foreign operations, whose functional currencies differ from the Group’s presentation currency, are translated into the Group’s presentation currency using the following procedures.

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Assets and liabilities for each statement of financial position presented are translated at the closing rate at the end of the reporting period. Income and expenses in the statement of comprehensive income presented are translated at average exchange rates for the period. All resulting exchange differences are recognized in other comprehensive income.

Any goodwill arising from the acquisition of a foreign operation and any fair value adjustments to the carrying amounts of assets and liabilities arising from the acquisition of that foreign operation are treated as assets and liabilities of the foreign operation. Thus, they are expressed in the functional currency of the foreign operation and are translated into the presentation currency at the closing rate.

On the disposal of a foreign operation, the cumulative amount of the exchange differences relating to that foreign operation, recognized in other comprehensive income and accumulated in the separate component of equity, is reclassified from equity to profit or loss (as a reclassification adjustment) when the gains or losses on disposal are recognized. On the partial disposal of a subsidiary that includes a foreign operation, the Group redistributes the proportionate share of the cumulative amount of the exchange differences recognized in other comprehensive income to the non-controlling interests in that foreign operation. In any other partial disposal of a foreign operation, the Group reclassifies to profit or loss only the proportionate share of the cumulative amount of the exchange differences recognized in other comprehensive income.

3.3 Recognition and Measurement of Financial Instruments

3.3.1 Initial recognition

The Group recognizes a financial asset or a financial liability in its statement of financial position when the Group becomes a party to the contractual provisions of the instrument. A regular way purchase or sale of financial assets (a purchase or sale of a financial asset under a contract whose terms require delivery of the financial instruments within the time frame established generally by market regulation or practice) is recognized and derecognized using trade date accounting.

The Group classifies financial assets as financial assets at fair value through profit or loss, held-to-maturity financial assets, available-for-sale financial assets, or loans and receivables, or other financial assets. The Group classifies financial liabilities as financial liabilities at fair value through profit or loss, or other financial liabilities. The classification depends on the nature and holding purpose of the financial instrument at initial recognition in the consolidated financial statements.

At initial recognition, a financial asset or financial liability is measured at its fair value plus or minus, in the case of a financial asset or financial liability not at fair value through profit or loss, transaction costs that are directly attributable to the acquisition or issue of the financial asset or financial liability. The fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. The fair value of a financial instrument on initial recognition is normally the transaction price (that is, the fair value of the consideration given or received) in an arm’s length transaction.

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3.3.2 Subsequent measurement

After initial recognition, financial instruments are measured at amortized cost or fair value based on classification at initial recognition.

Amortized cost

The amortized cost of a financial asset or financial liability is the amount at which the financial asset or financial liability is measured at initial recognition and adjusted to reflect principal repayments, cumulative amortization using the effective interest method and any reduction (directly or through the use of an allowance account) for impairment or uncollectibility.

Fair value

Fair values, which the Group primarily uses for the measurement of financial instruments, are the published price quotations based on market prices or dealer price quotations of financial instruments traded in an active market where available. These are the best evidence of fair value. A financial instrument is regarded as quoted in an active market if quoted prices are readily and regularly available from an exchange, dealer, broker, an entity in the same industry, pricing service or regulatory agency, and those prices represent actual and regularly occurring market transactions on an arm’s length basis.

If the market for a financial instrument is not active, fair value is determined either by using a valuation technique or independent third-party valuation service. Valuation techniques include using recent arm’s length market transactions between knowledgeable, willing parties, if available, referencing to the current fair value of another instrument that is substantially the same, discounted cash flow analysis and option pricing models.

The Group uses valuation models that are commonly used by market participants and customized for the Group to determine fair values of common over-the-counter (OTC) derivatives such as options, interest rate swaps and currency swaps which are based on the inputs observable in markets. For more complex instruments, the Group uses internally developed models, which are usually based on valuation methods and techniques generally used within the industry, or a value measured by an independent external valuation institution as the fair values if all or some of the inputs to the valuation models are not market observable and therefore it is necessary to estimate fair value based on certain assumptions.

The Group’s Fair Value Evaluation Committee, which consists of the risk management department, trading department and accounting department, reviews the appropriateness of internally developed valuation models, and approves the selection and changing of the external valuation institution and other considerations related to fair value measurement. The review results on the fair valuation models are reported to the Market Risk Management subcommittee by the Fair Value Evaluation Committee on a regular basis.

If the valuation technique does not reflect all factors which market participants would consider in setting a price, the fair value is adjusted to reflect those factors. Those factors include counterparty credit risk, bid-ask spread, liquidity risk and others.

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December 31, 2017 and 2016

The chosen valuation technique makes maximum use of market inputs and relies as little as possible on entity-specific inputs. It incorporates all factors that market participants would consider in setting a price and is consistent with economic methodologies applied for pricing financial instruments. Periodically, the Group calibrates the valuation technique and tests its validity using prices of observable current market transactions of the same instrument or based on other relevant observable market data.

3.3.3 Derecognition

Derecognition is the removal of a previously recognized financial asset or financial liability from the statement of financial position. The Group derecognizes a financial asset or a financial liability when, and only when:

Derecognition of financial assets

Financial assets are derecognized when the contractual rights to the cash flows from the financial assets expire or the financial assets have been transferred and substantially all the risks and rewards of ownership of the financial assets are also transferred, or all the risks and rewards of ownership of the financial assets are neither substantially transferred nor retained and the Group has not retained control. If the Group neither transfers nor disposes of substantially all the risks and rewards of ownership of the financial assets, the Group continues to recognize the financial asset to the extent of its continuing involvement in the financial asset.

If the Group transfers the contractual rights to receive the cash flows of the financial asset, but retains substantially all the risks and rewards of ownership of the financial asset, the Group continues to recognize the transferred asset in its entirely and recognize a financial liability for the consideration received.

Derecognition of financial liabilities

Financial liabilities are derecognized from the statement of financial position when the obligation specified in the contract is discharged, cancelled or expires.

3.3.4 Offsetting

Financial assets and liabilities are offset and the net amount reported in the consolidated statements of financial position where there is a legally enforceable right to offset the recognized amounts and there is an intention to settle on a net basis or realize the assets and settle the liability simultaneously. The legally enforceable right must not be contingent on future events and must be enforceable in the normal course of business and in the event of default, insolvency or bankruptcy of the Group or the counterparty.

3.4 Cash and Cash Equivalents

Cash and cash equivalents include cash on hand, foreign currency, and short-term, highly liquid investments that are readily convertible to known amounts of cash and which are subject to an insignificant risk of changes in value.

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3.5 Non-derivative Financial Assets

3.5.1 Financial assets at fair value through profit or loss

This category comprises two sub-categories: financial assets classified as held for trading, and financial assets designated by the Group as at fair value through profit or loss upon initial recognition.

A non-derivative financial asset is classified as held for trading if either:

The Group may designate certain financial assets, other than held for trading, upon initial recognition as at fair value through profit or loss when one of the following conditions is met:

After initial recognition, a financial asset at fair value through profit or loss is measured at fair value and gains or losses arising from a change in the fair value are recognized in profit or loss. Interest income, dividend income, and gains or losses from sale and repayment from financial assets at fair value through profit or loss are recognized in the statement of comprehensive income as net gains on financial instruments at fair value through profit or loss.

3.5.2 Financial Investments

Available-for-sale and held-to-maturity financial assets are presented as financial investments.

Available-for-sale financial assets

Profit or loss of financial assets classified as available for sale, except for impairment loss and foreign exchange gains and losses resulting from changes in amortized cost of debt securities, is recognized as other comprehensive income, and cumulative profit or loss is reclassified from equity to current profit or loss at the derecognition of the financial asset, and it is recognized as part of other operating profit or loss in the statement of comprehensive income.

However, interest income measured using the effective interest method is recognized in current profit or loss, and dividends of financial assets classified as available-for-sale are recognized when the right to receive payment is established.

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December 31, 2017 and 2016

Available-for-sale financial assets denominated in foreign currencies are translated at the closing rate. For available-for-sale debt securities denominated in foreign currency, exchange differences resulting from changes in amortized cost are recognized in profit or loss as part of other operating income and expenses. For available-for-sale equity securities denominated in foreign currency, the entire change in fair value including any exchange component is recognized in other comprehensive income.

Held-to-maturity financial assets