UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

(MARK ONE)

For the quarterly period ended JuneSeptember 30, 2016

OR

For the transition period from                    to                    

Commission file number 000-04887

UMB FINANCIAL CORPORATION

(Exact name of registrant as specified in its charter)

(Registrant’s telephone number, including area code): (816) 860-7000

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yesx    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    YesxNo  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes¨    YesNo  x  No

Indicate the number of shares outstanding of each of the issuer’s classes of common stock as of the latest practicable date.

As of July 28,October 27, 2016, UMB Financial Corporation had 49,529,83049,562,002 shares of common stock outstanding.

UMB FINANCIAL CORPORATION

FORM 10-Q

INDEX

PART I – FINANCIAL INFORMATION

ITEM 1. FINANCIAL STATEMENTS

UMB FINANCIAL CORPORATION

CONSOLIDATED BALANCE SHEETS

(unaudited, dollars in thousands, except share and per share data)

See Notes to Consolidated Financial Statements.

UMB FINANCIAL CORPORATION

CONSOLIDATED STATEMENTS OF INCOME

(unaudited, dollars in thousands, except share and per share data)

See Notes to Consolidated Financial Statements.

UMB FINANCIAL CORPORATION

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME

(unaudited, dollars in thousands)

See Notes to Consolidated Financial Statements.

UMB FINANCIAL CORPORATION

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS’ EQUITY

(unaudited, dollars in thousands, except per share data)

See Notes to Consolidated Financial Statements.

UMB FINANCIAL CORPORATION

CONSOLIDATED STATEMENTS OF CASH FLOWS

(unaudited, dollars in thousands)

See Notes to Consolidated Financial Statements.

UMB FINANCIAL CORPORATION

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

FOR THE THREE AND SIXNINE MONTHS ENDED JUNESEPTEMBER 30, 2016 (UNAUDITED)

1. Financial Statement Presentation

The consolidated financial statements include the accounts of UMB Financial Corporation and its subsidiaries (collectively, the Company) after elimination of all intercompany transactions. In the opinion of management of the Company, all adjustments relating to items that are of a normal recurring nature and necessary for a fair presentation of the financial position and results of operations have been made. The results of operations and cash flows for the interim periods presented may not be indicative of the results of the full year. The financial statements should be read in conjunction with “Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations” within this Quarterly Report on Form 10-Q (the Form 10-Q) and in conjunction with the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2015 filed with the Securities and Exchange Commission (SEC) on February 25, 2016 (the Form 10-K).

2. Summary of Significant Accounting Policies

The Company is a financial holding company, which offers a wide range of banking and other financial services to its customers through its branches and offices in Missouri, Kansas, Colorado, Illinois, Oklahoma, Texas, Arizona, Nebraska, Pennsylvania, South Dakota, Indiana, Utah, Minnesota, California, and Wisconsin. The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (U.S. GAAP) requires management to make estimates and assumptions that affect the reported amount of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements. These estimates and assumptions also impact reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. A summary of the significant accounting policies to assist the reader in understanding the financial presentation is provided in the Notes to Consolidated Financial Statements in the Form 10-K.

Cash and cash equivalents

Cash and cash equivalents include Cash and due from banks and amounts due from the Federal Reserve Bank. Cash on hand, cash items in the process of collection, and amounts due from correspondent banks are included in Cash and due from banks. Amounts due from the Federal Reserve Bank are interest-bearing for all periods presented and are included in the Interest-bearing due from banks line on the Company’s Consolidated Balance Sheets.

This table provides a summary of cash and cash equivalents as presented on the Consolidated Statements of Cash Flows as of JuneSeptember 30, 2016 and JuneSeptember 30, 2015 (in thousands):

Also included in the Interest-bearing due from banks, line, but not considered cash and cash equivalents, are interest-bearing accounts held at other financial institutions, which totaled $109.5$96.8 million and $177.3$155.9 million at JuneSeptember 30, 2016 and JuneSeptember 30, 2015, respectively.

Per Share Data

Basic net income per share is computed based on the weighted average number of shares of common stock outstanding during each period. Diluted quarter-to-date net income per share includes the dilutive effect of 394,738435,029 and 370,227459,050 shares issuable upon the exercise of options granted by the Company and outstanding at JuneSeptember 30, 2016 and 2015, respectively. Diluted year-to-date net income per share includes the dilutive effect of 362,517369,781 and 405,702460,581 shares issuable upon the exercise of stock options granted by the Company and outstanding at JuneSeptember 30, 2016 and 2015, respectively.

UMB FINANCIAL CORPORATION

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS –(CONTINUED)

FOR THE THREE AND SIXNINE MONTHS ENDED JUNESEPTEMBER 30, 2016 (UNAUDITED)

Options issued under employee benefits plans to purchase 637,331394,863 shares of common stock were outstanding at JuneSeptember 30, 2016, but were not included in the computation of quarter-to-date anddiluted EPS because the options were anti-dilutive. Options issued under employee benefits plans to purchase 628,698 shares of common stock were outstanding at September 30, 2016, but were not included in the computation of year-to-date diluted EPS because the options were anti-dilutive. Options issued under employee benefits plans to purchase 495,366461,905 shares of common stock were outstanding at JuneSeptember 30, 2015, but were not included in the computation of quarter-to-date and year-to-date diluted EPS because the options were anti-dilutive.

3. New Accounting Pronouncements

Revenue RecognitionIn May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-09, “Revenue from Contracts with Customers.” The issuance is part of a joint effort by the FASB and the International Accounting Standards Board (IASB) to enhance financial reporting by creating common revenue recognition guidance for U.S. GAAP and International Financial Reporting Standards (IFRS) and, thereby, improving the consistency of requirements, comparability of practices and usefulness of disclosures. The ASU will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. In AugustNovember 2015, the FASB issued ASU No. 2015-14, which deferred the effective date of ASU No. 2014-09 to annual reporting periods that begin after December 15, 2017. In March 2016, the FASB issued ASU No. 2016-08, which intends to improve the operability and understandability of the implementation guidance on principal versus agent considerations within ASU No. 2014-09. In April 2016, the FASB issued ASU No. 2016-10, which clarifies guidance related to identifying performance obligations and licensing implementation within ASU No. 2014-09. In May 2016, the FASB issued ASU Nos. 2016-11 and 2016-12, which further clarify guidance and provide practical expedients related to the adoption of ASU No. 2014-09. The standard permits the use of either the retrospective or cumulative effect transition method. The Company is currently evaluating the effect that these standards will have on its Consolidated Financial Statements and related disclosures. The Company has not yet selected a transition method nor has it determined the effect of the standard on its ongoing financial reporting.method.

Equity-Based CompensationIn June 2014, the FASB issued ASU No. 2014-12, “Accounting for Share-Based Payments When the Terms of an Award Provide that a Performance Target could be Achieved after the Requisite Service Period.” The amendment is intended to reduce diversity in practice by clarifying that a performance target that affects vesting and that could be achieved after the requisite service period be treated as a performance condition. The amendments in this update were effective for interim and annual periods beginning after December 15, 2015. The adoption of this accounting pronouncement had no impact on the Company’s Consolidated Financial Statements.

Going Concern In AugustNovember 2014, the FASB issued ASU No. 2014-15, “Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern.” The amendment addresses management’s responsibility in regularly evaluating whether there is substantial doubt about a company’s ability to continue as a going concern. The amendments in this update are effective for the annual period ending after December 15, 2016, and for annual and interim periods thereafter, although early adoption is permitted. The adoption of this accounting pronouncement will not impact the Company’s Consolidated Financial Statements.

Derivatives and Hedging In November 2014, the FASB issued ASU No. 2014-16, “Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share is More Akin to Debt or to Equity.” The amendment is intended to address how current U.S. GAAP should be interpreted in evaluating the economic characteristics and risks of a host contract in a hybrid financial instrument that is issued in the form of a share. The amendments in this update were effective for interim and annual periods beginning after December 15, 2015. The adoption of this accounting pronouncement had no impact on the Company’s Consolidated Financial Statements.

ConsolidationIn February 2015, the FASB issued ASU No. 2015-02, “Amendments to the Consolidation Analysis.” The amendment substantially changes the way reporting entities are required to evaluate whether they should consolidate certain legal entities. All legal entities are subject to reevaluation under the new amendment. Specifically, the amendments modify the evaluation of whether limited partnerships and similar legal entities are variable interest entities (VIEs) or voting interest entities, eliminate the presumption that a general partner should consolidate a limited partnership, and affect the consolidation analysis of reporting entities that are involved with VIEs. The amendments in this update were effective for interim and annual periods beginning after December 15, 2015. The standard permits the use of either the retrospective or cumulative effect transition method. The adoption of this accounting pronouncement had no impact on the Company’s Consolidated Financial Statements.

UMB FINANCIAL CORPORATION

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS –(CONTINUED)

FOR THE THREE AND SIXNINE MONTHS ENDED JUNESEPTEMBER 30, 2016 (UNAUDITED)

Financial Instruments In January 2016, the FASB issued ASU No. 2016-01, “Recognition and Measurement of Financial Assets and Financial Liabilities.” The amendment is intended to address certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. The amendments in this update are effective for interim and annual periods beginning after December 15, 2017. The standard requires the use of the cumulative effect transition method as of the beginning of the year of adoption. Except for certain provisions, early adoption is not permitted. The Company is currently evaluating the impact this will have on its Consolidated Financial Statements.

LeasesIn February 2016, the FASB issued ASU No. 2016-02, “Leases.” The amendment changes the accounting treatment of leases, in that lessees will recognize most leases on-balance sheet. This will increase reported assets and liabilities, as lessees will be required to recognize a right-of-use asset along with a lease liability, measured on a discounted basis. Lessees are allowed to account for short-term leases (those with a term of twelve months or less) off-balance sheet. The amendments in this update are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The standard requires the use of the modified retrospective transition method. Early adoption is permitted. The Company is currently evaluating the impact this will have on its Consolidated Financial Statements.

Extinguishments of LiabilitiesIn March 2016, the FASB issued ASU No. 2016-04, “Recognition of Breakage for Certain Prepaid Stored-Value Products.” The amendment is intended to reduce the diversity in practice related to the recognition of breakage. Breakage refers to the portion of a prepaid stored-value product, such as a gift card, that goes unused wholly or partially for an indefinite period of time. This amendment requires that breakage be accounted for consistent with the breakage guidance within ASU No. 2014-09, “Revenue from Contracts with Customers.” The amendments in this update are effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The standard permits the use of either the modified retrospective or full retrospective transition method. Early adoption is permitted. The Company is currently evaluating the effect that ASU No. 2016-04 will have on its Consolidated Financial Statements. The Company has not yet selected a transition method nor has it determined the effect of the standard on its ongoing financial reporting. The Company will adopt ASU No. 2016-04 in conjunction with its adoption of ASU No. 2014-09.

Derivatives and HedgingIn March 2016, the FASB issued ASU No. 2016-05, “Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships.” The amendment is intended to clarify that the novation of a derivative contract that has been designated to be in a hedging relationship under Accounting Standards Codification (ASC) Topic 815 does not, in and of itself, represent a termination event for the derivative and does not require dedesignation of the hedging relationship. The amendments in this update are effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. The amendment permits the use of either a prospective or modified retrospective transition method. Early adoption is permitted. The adoption of this accounting pronouncement will have no impact on the Company’s Consolidated Financial Statements.

Equity-Based CompensationIn March 2016, the FASB issued ASU No. 2016-09, “Improvements to Employee Share-Based Payment Accounting.” The amendment is part of the FASB’s simplification initiative and is intended to simplify the accounting around share-based payment award transactions. The amendments include changing the recording of excess tax benefits from being recognized as a part of surplus capital to being charged directly to the income statement, changing the classification of excess tax benefits within the statement of cash flows, and allowing companies to account for forfeitures on an actual basis, as well as tax withholding changes. The amendment requires different transition methods for various components of the standard. The amendments in this update are effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. The amendment requires different transition methods for various components of the standard. Early adoption is permitted.

In September 2016, the Company early adopted ASU No. 2016-09 with an effective date of January 1, 2016. As part of the adoption of this standard, the Company made an accounting policy election to account for forfeitures on an actual basis and discontinue the use of an estimated forfeiture approach. Additionally, the Company selected the retrospective transition method for the reclassification of the “Net tax benefit related to equity compensation plans” from the financing section to the operating section of the Company’s Consolidated Statement of Cash Flows. The

UMB FINANCIAL CORPORATION

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS –(CONTINUED)

FOR THE THREE AND NINE MONTHS ENDED SEPTEMBER 30, 2016 (UNAUDITED)

impact to the Company’s Consolidated Statements of Income for adopting all provisions of the standard was an increase to net income of $158 thousand for the three-month period ended March 31, 2016 and an increase to net income of $220 thousand for the three-month period ended June 30, 2016. Upon adoption, the Company is currently evaluatingrecorded a cumulative effect adjustment of $482 thousand as an increase to the impact thisopening balance of total equity. Prior period financial statements as of and for the three-month and year-to-date periods ended March 31, 2016 and June 30, 2016 will have on its Consolidated Financial Statements.be recast when presented in future filings.

Credit LossesIn June 2016, the FASB issued ASU 2016-13, “Measurement of Credit Losses on Financial Instruments.” This update replaces the current incurred loss methodology for recognizing credit losses with a current expected credit loss model, which requires the measurement of all expected credit losses for financial assets held at the reporting date based on historical experience, current conditions, and reasonable and supportable forecasts. This amendment broadens the information that an entity must consider in developing its expected credit loss estimates. Additionally, the update amends the accounting for credit losses for available-for-sale debt securities

UMB FINANCIAL CORPORATION

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS –(CONTINUED)

FOR THE THREE AND SIX MONTHS ENDED JUNE 30, 2016 (UNAUDITED)

and purchased financial assets with a more-than-insignificant amount of credit deterioration since origination. This update requires enhanced disclosures to help investors and other financial statement users better understand significant estimates and judgments used in estimating credit losses, as well as the credit quality and underwriting standards of a company’s loan portfolio. The amendments in this update are effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption in fiscal years beginning after December 15, 2018 is permitted. The amendment requires the use of the modified retrospective approach for adoption. The Company is currently evaluating the impact this will have on its Consolidated Financial Statements.

Statement of Cash FlowsIn August 2016, the FASB issued ASU 2016-15,“Classification of Certain Receipts and Cash Payments.” This amendment adds to and clarifies existing guidance regarding the classification of certain cash receipts and payments in the statement of cash flows with the intent of reducing diversity in practice with respect to eight types of cash flows. The amendments in this update require full retrospective adoption and are effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is permitted. The Company is currently evaluating the impact this will have on its Consolidated Statement of Cash Flows.

4. Loans and Allowance for Loan Losses

Loan Origination/Risk Management

The Company has certain lending policies and procedures in place that are designed to minimize the level of risk within the loan portfolio. Diversification of the loan portfolio manages the risk associated with fluctuations in economic conditions. Authority levels are established for the extension of credit to ensure consistency throughout the Company. It is necessary that policies, processes and practices implemented to control the risks of individual credit transactions and portfolio segments are sound and adhered to. The Company maintains an independent loan review department that reviews and validates the risk assessment on a continual basis. Management regularly evaluates the results of the loan reviews. The loan review process complements and reinforces the risk identification and assessment decisions made by lenders and credit personnel, as well as the Company’s policies and procedures.

Commercial loans are underwritten after evaluating and understanding the borrower’s ability to operate profitably and prudently expand its business. Commercial loans are made based on the identified cash flows of the borrower and on the underlying collateral provided by the borrower. The cash flows of the borrower, however, may not be as expected and the collateral securing these loans may fluctuate in value. Most commercial loans are secured by the assets being financed or other business assets such as accounts receivable or inventory and may incorporate a personal guarantee. In the case of loans secured by accounts receivable, the availability of funds for the repayment of these loans may be substantially dependent on the ability of the borrower to collect amounts from its customers. Commercial credit cards are generally unsecured and are underwritten with criteria similar to commercial loans including an analysis of the borrower’s cash flow, available business capital, and overall credit-worthiness of the borrower.

Asset-based loans are offered primarily in the form of revolving lines of credit to commercial borrowers that do not generally qualify for traditional bank financing. Asset-based loans are underwritten based primarily upon the value of the collateral pledged to secure the loan, rather than on the borrower’s general financial condition as traditionally reflected by cash flow, balance sheet strength, operating results, and credit bureau ratings.condition. The Company utilizes pre-loan due diligence techniques, monitoring disciplines, and loan management practices common within the asset-based lending industry to underwrite loans to these borrowers.

UMB FINANCIAL CORPORATION

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS –(CONTINUED)

FOR THE THREE AND NINE MONTHS ENDED SEPTEMBER 30, 2016 (UNAUDITED)

Factoring loans provide working capital through the purchase and/or financing of accounts receivable to borrowers in the transportation industry and to commercial borrowers that do not generally qualify for traditional bank financing.

Commercial real estate loans are subject to underwriting standards and processes similar to commercial loans, in addition to those of real estate loans. These loans are viewed primarily as cash flow loans and secondarily as loans secured by real estate. Commercial real estate lending typically involves higher loan principal amounts, and the repayment of these loans is largely dependent on the successful operation of the property securing the loan or the business conducted on the property securing the loan. The Company requires that an appraisal of the collateral be made at origination and on an as-needed basis, in conformity with current market conditions and regulatory requirements. The underwriting standards address both owner and non-owner occupied real estate.

Construction loans are underwritten using feasibility studies, independent appraisal reviews, sensitivity analysis or absorption and lease rates and financial analysis of the developers and property owners. Construction loans are based upon estimates of costs and value associated with the complete project. Construction loans often involve the disbursement of substantial funds with repayment substantially dependent on the success of the ultimate project. Sources of repayment for these types of loans may be pre-committed permanent loans, sales of developed

UMB FINANCIAL CORPORATION

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS –(CONTINUED)

FOR THE THREE AND SIX MONTHS ENDED JUNE 30, 2016 (UNAUDITED)

property or an interim loan commitment from the Company until permanent financing is obtained. These loans are closely monitored by on-site inspections and are considered to have higher risks than other real estate loans due to their repayment being sensitive to interest rate changes, governmental regulation of real property, economic conditions, and the availability of long-term financing.

Underwriting standards for residential real estate and home equity loans are based on the borrower’s loan-to-value percentage, collection remedies, and overall credit history.

Consumer loans are underwritten based on the borrower’s repayment ability. The Company monitors delinquencies on all of its consumer loans and leases and periodically reviews the distribution of FICO scores relative to historical periods to monitor credit risk on its credit card loans. The underwriting and review practices combined with the relatively small loan amounts that are spread across many individual borrowers, minimizes risk. Consumer loans and leases that are 90 days past due or more are considered non-performing.

Credit risk is a potential loss resulting from nonpayment of either the primary or secondary exposure. Credit risk is mitigated with formal risk management practices and a thorough initial credit-granting process including consistent underwriting standards and approval process. Control factors or techniques to minimize credit risk include knowing the client, understanding total exposure, analyzing the client and debtor’s financial capacity, and monitoring the client’s activities. Credit risk and portions of the portfolio risk are managed through concentration considerations, average risk ratings, and other aggregate characteristics.

The loan portfolio is comprised of loans originated by the Company and loans purchased in connection with the Company’s acquisition of Marquette Financial Companies (Marquette) on May 31, 2015 (the Acquisition Date). The purchased loans were recorded at estimated fair value at the Acquisition Date with no carryover of the related allowance. The purchased loans were segregated between those considered to be performing, non-purchased credit impaired loans (Non-PCI), and those with evidence of credit deterioration, purchased credit impaired loans (PCI). Purchased loans are considered impaired if there is evidence of credit deterioration and if it is probable, at acquisition, that all contractually required payments will not be collected.

At the Acquisition Date, gross loans purchased from the Marquette acquisition had a fair value of $980.4 million split between Non-PCI loans totaling $972.6 million and PCI loans totaling $7.8 million of loans. The gross contractually required principal and interest payments receivable for the Non-PCI loans and PCI loans totaled $983.9 million and $9.3 million, respectively.

The fair value estimates for purchased loans are based on expected prepayments and the amount and timing of discounted expected principal, interest and other cash flows. Credit discounts representing the principal losses

UMB FINANCIAL CORPORATION

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS –(CONTINUED)

FOR THE THREE AND NINE MONTHS ENDED SEPTEMBER 30, 2016 (UNAUDITED)

expected over the life of the loan are also a component of the initial fair value. In determining the Acquisition Date fair value of PCI loans, and in subsequent accounting, the Company generally aggregated purchased commercial, real estate, and consumer loans into pools of loans with common risk characteristics.

The difference between the fair value of Non-PCI loans and contractual amounts due at the Acquisition Date is accreted into income over the estimated life of the loans. Contractual amounts due represent the total undiscounted amount of all uncollected principal and interest payments.

Loans accounted for under ASC Topic 310-30

The excess of PCI loans’ contractual amounts due over the amount of undiscounted cash flows expected to be collected is referred to as the non-accretable difference. The non-accretable difference, which is neither accreted into income nor recorded on the consolidated balance sheet, reflects estimated future credit losses and uncollectible contractual interest expected to be incurred over the life of the PCI loans. The excess cash flows expected to be collected over the carrying amount of PCI loans is referred to as the accretable yield. This amount is accreted into interest income over the remaining life of the purchased loans or pools using the level yield method. The accretable yield is affected by changes in interest rate indices for variable rate loans, changes in prepayment speed assumptions, and changes in expected principal and interest payments over the estimated lives of the PCI loans.

UMB FINANCIAL CORPORATION

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS –(CONTINUED)

FOR THE THREE AND SIX MONTHS ENDED JUNE 30, 2016 (UNAUDITED)

Each quarter the Company evaluates the remaining contractual amounts due and estimates cash flows expected to be collected over the life of the PCI loans. Contractual amounts due may increase or decrease for a variety of reasons, for example, when the contractual terms of the loan agreement are modified, when interest rates on variable rate loans change, or when principal and/or interest payments are received. Cash flows expected to be collected on PCI loans are estimated by incorporating several key assumptions similar to the initial estimate of fair value. These key assumptions include probability of default, loss given default, and the amount of actual prepayments after the Acquisition Date. Prepayments affect the estimated lives of loans and could change the amount of interest income, and possibly principal, expected to be collected. In re-forecasting future estimated cash flows, credit loss expectations are adjusted as necessary. The adjustments are based, in part, on actual loss severities recognized for each loan type, as well as changes in the probability of default. For periods in which estimated cash flows are not reforecasted, the prior reporting period’s estimated cash flows are adjusted to reflect the actual cash received and credit events that transpired during the current reporting period.

Increases in expected cash flows of PCI loans subsequent to the Acquisition Date are recognized prospectively through adjustments of the yield on the loans or pools over their remaining lives, while decreases in expected cash flows are recognized as impairment through a provision for loan losses and an increase in the allowance.

The PCI loans are accounted for in accordance with ASC Topic 310-30,Loans and Debt Securities Purchased with Deteriorated Credit Quality. At JuneSeptember 30, 2016, the net recorded carrying amount of loans accounted for under ASC 310-30 was $2.2$1.0 million and the contractual amount due was $3.0$1.2 million.

Below is the composition of the net book value for the PCI loans accounted for under ASC 310-30 at JuneSeptember 30, 2016(in thousands):

UMB FINANCIAL CORPORATION

NOTES TO THE CONSOLIDATED FINANCIAL STATEMENTS –(CONTINUED)

FOR THE THREE AND SIXNINE MONTHS ENDED JUNESEPTEMBER 30, 2016 (UNAUDITED)

Loan Aging Analysis

This table provides a summary of loan classes and an aging of past due loans at JuneSeptember 30, 2016 and December 31, 2015(in thousands):