Table of Contents


United States
Securities and Exchange Commission
Washington, D.C. 20549
Form 10-Q
ý Quarterly Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934
For the quarterly period ended: September 30, 2017March 31, 2019
Or
¨ Transition Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934
For the transition period from                    to
Commission file number: 001-13221
Cullen/Frost Bankers, Inc.
(Exact name of registrant as specified in its charter)
Texas74-1751768
(State or other jurisdiction of
incorporation or organization)
(I.R.S. Employer
Identification No.)
  
100 W. Houston Street, San Antonio, Texas78205
(Address of principal executive offices)(Zip code)
(210) 220-4011
(Registrant’s telephone number, including area code)
N/A
(Former name, former address and former fiscal year, if changed since last report)
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.     Yes  ý    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).    Yes  ý    No  ¨
Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.
Large accelerated filerýAccelerated filer¨
Non-accelerated filer
¨ (Do not check if a smaller reporting company)
Smaller reporting company¨
  Emerging growth company¨
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.    ¨
Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes  ¨    No  ý
As of October 19, 2017April 18, 2019 there were 63,164,49163,093,256 shares of the registrant’s Common Stock, $.01 par value, outstanding.

Cullen/Frost Bankers, Inc.
Quarterly Report on Form 10-Q
September 30, 2017March 31, 2019
Table of Contents
 Page
Item 1. 
 
 
 
 
 
 
Item 2.Management's Discussion and Analysis of Financial Condition and Results of Operations
Item 3.
Item 4.
   
 
Item 1.
Item 1A.
Item 2.
Item 3.
Item 4.
Item 5.
Item 6.
   

Part I. Financial Information
Item 1. Financial Statements (Unaudited)
Cullen/Frost Bankers, Inc.
Consolidated Balance Sheets
(Dollars in thousands, except per share amounts)
September 30,
2017
 December 31,
2016
March 31,
2019
 December 31,
2018
Assets:      
Cash and due from banks$503,961
 $561,838
$521,599
 $678,791
Interest-bearing deposits4,538,300
 3,560,865
1,435,088
 2,641,971
Federal funds sold and resell agreements49,642
 18,742
324,767
 635,017
Total cash and cash equivalents5,091,903
 4,141,445
2,281,454
 3,955,779
Securities held to maturity, at amortized cost1,442,222
 2,250,460
1,077,279
 1,106,057
Securities available for sale, at estimated fair value10,185,100
 10,203,277
12,013,963
 11,387,321
Trading account securities19,721
 16,703
25,231
 24,086
Loans, net of unearned discounts12,706,304
 11,975,392
14,406,339
 14,099,733
Less: Allowance for loan losses(154,303) (153,045)(136,350) (132,132)
Net loans12,552,001
 11,822,347
14,269,989
 13,967,601
Premises and equipment, net520,639
 525,821
750,256
 552,330
Goodwill654,952
 654,952
654,952
 654,952
Other intangible assets, net5,475
 6,776
3,324
 3,649
Cash surrender value of life insurance policies179,789
 177,884
184,371
 183,473
Accrued interest receivable and other assets338,170
 396,654
403,747
 457,718
Total assets$30,989,972
 $30,196,319
$31,664,566
 $32,292,966
      
Liabilities:      
Deposits:      
Non-interest-bearing demand deposits$11,174,251
 $10,513,369
$10,128,908
 $10,997,494
Interest-bearing deposits15,229,018
 15,298,206
16,165,955
 16,151,710
Total deposits26,403,269
 25,811,575
26,294,863
 27,149,204
Federal funds purchased and repurchase agreements997,919
 976,992
1,227,149
 1,367,548
Junior subordinated deferrable interest debentures, net of unamortized issuance costs136,170
 136,127
136,256
 136,242
Subordinated notes, net of unamortized issuance costs98,512
 99,990
98,747
 98,708
Accrued interest payable and other liabilities165,059
 169,107
313,973
 172,347
Total liabilities27,800,929
 27,193,791
28,070,988
 28,924,049
      
Shareholders’ Equity:      
Preferred stock, par value $0.01 per share; 10,000,000 shares authorized; 6,000,000 Series A shares ($25 liquidation preference) issued at September 30, 2017 and December 31, 2016144,486
 144,486
Common stock, par value $0.01 per share; 210,000,000 shares authorized; 64,236,306 shares issued at September 30, 2017 and 63,632,464 shares issued at December 31, 2016642
 637
Preferred stock, par value $0.01 per share; 10,000,000 shares authorized; 6,000,000 Series A shares ($25 liquidation preference) issued at March 31, 2019 and December 31, 2018144,486
 144,486
Common stock, par value $0.01 per share; 210,000,000 shares authorized; 64,236,306 shares issued at March 31, 2019 and December 31, 2018642
 642
Additional paid-in capital951,893
 906,732
970,958
 967,304
Retained earnings2,133,259
 1,985,569
2,495,268
 2,440,002
Accumulated other comprehensive income, net of tax57,675
 (24,623)
Treasury stock, at cost; 1,122,721 shares at September 30, 2017 and 158,243 shares at December 31, 2016(98,912) (10,273)
Accumulated other comprehensive income (loss), net of tax93,774
 (63,600)
Treasury stock, at cost; 1,154,950 shares at March 31, 2019 and 1,250,464 shares at December 31, 2018(111,550) (119,917)
Total shareholders’ equity3,189,043
 3,002,528
3,593,578
 3,368,917
Total liabilities and shareholders’ equity$30,989,972
 $30,196,319
$31,664,566
 $32,292,966
See Notes to Consolidated Financial Statements.



Cullen/Frost Bankers, Inc.
Consolidated Statements of Income
(Dollars in thousands, except per share amounts)
Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
Three Months Ended 
 March 31,
2017 2016 2017 20162019 2018
Interest income:          
Loans, including fees$138,400
 $114,368
 $392,073
 $340,303
$185,272
 $151,202
Securities:          
Taxable23,203
 25,897
 72,032
 77,402
24,679
 20,558
Tax-exempt54,939
 53,065
 167,321
 154,308
59,143
 56,711
Interest-bearing deposits10,800
 4,111
 26,712
 11,366
10,639
 14,094
Federal funds sold and resell agreements244
 48
 514
 165
1,588
 761
Total interest income227,586
 197,489
 658,652
 583,544
281,321
 243,326
Interest expense:          
Deposits5,668
 1,749
 9,709
 5,309
27,174
 10,638
Federal funds purchased and repurchase agreements523
 44
 849
 152
5,016
 634
Junior subordinated deferrable interest debentures1,020
 839
 2,890
 2,392
1,498
 1,142
Other long-term borrowings1,164
 350
 2,696
 958
1,164
 1,164
Total interest expense8,375
 2,982
 16,144
 8,811
34,852
 13,578
Net interest income219,211
 194,507
 642,508
 574,733
246,469
 229,748
Provision for loan losses10,980
 5,045
 27,358
 42,734
11,003
 6,945
Net interest income after provision for loan losses208,231
 189,462
 615,150
 531,999
235,466
 222,803
Non-interest income:          
Trust and investment management fees27,493
 26,451
 81,690
 77,806
31,697
 29,587
Service charges on deposit accounts20,967
 20,540
 62,934
 60,769
20,790
 20,843
Insurance commissions and fees10,892
 11,029
 34,441
 35,812
18,406
 15,980
Interchange and debit card transaction fees5,884
 5,435
 17,150
 15,838
3,280
 3,158
Other charges, commissions and fees10,493
 10,703
 29,983
 29,825
9,062
 9,007
Net gain (loss) on securities transactions(4,867) (37) (4,917) 14,866

 (19)
Other10,753
 7,993
 25,114
 21,358
13,550
 12,889
Total non-interest income81,615
 82,114
 246,395
 256,274
96,785
 91,445
Non-interest expense:          
Salaries and wages84,388
 79,411
 247,895
 236,814
92,476
 86,683
Employee benefits17,730
 17,844
 57,553
 55,861
23,526
 21,995
Net occupancy19,391
 18,202
 57,781
 53,631
19,267
 19,740
Furniture and equipment18,743
 17,979
 54,983
 53,474
Technology, furniture and equipment21,664
 19,679
Deposit insurance4,862
 4,558
 15,347
 12,412
2,808
 4,879
Intangible amortization405
 586
 1,301
 1,869
325
 388
Other41,304
 41,925
 127,929
 125,048
41,734
 43,247
Total non-interest expense186,823
 180,505
 562,789
 539,109
201,800
 196,611
Income before income taxes103,023
 91,071
 298,756
 249,164
130,451
 117,637
Income taxes9,892
 10,852
 35,131
 28,622
13,955
 11,157
Net income93,131
 80,219
 263,625
 220,542
116,496
 106,480
Preferred stock dividends2,016
 2,016
 6,047
 6,047
2,016
 2,016
Net income available to common shareholders$91,115
 $78,203
 $257,578
 $214,495
$114,480
 $104,464
          
Earnings per common share:          
Basic$1.43
 $1.24
 $4.02
 $3.44
$1.80
 $1.63
Diluted1.41
 1.24
 3.98
 3.42
1.79
 1.61
See Notes to Consolidated Financial Statements.

Cullen/Frost Bankers, Inc.
Consolidated Statements of Comprehensive Income (Loss)
(Dollars in thousands)
Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
Three Months Ended 
 March 31,
2017 2016 2017 20162019 2018
Net income$93,131
 $80,219
 $263,625
 $220,542
$116,496
 $106,480
Other comprehensive income (loss), before tax:          
Securities available for sale and transferred securities:          
Change in net unrealized gain/loss during the period7,082
 (95,641) 131,283
 191,865
198,146
 (178,904)
Change in net unrealized gain on securities transferred to held to maturity(3,514) (7,278) (13,660) (24,629)(344) (2,619)
Reclassification adjustment for net (gains) losses included in net income4,867
 37
 4,917
 (14,866)
 19
Total securities available for sale and transferred securities8,435
 (102,882) 122,540
 152,370
197,802
 (181,504)
Defined-benefit post-retirement benefit plans:          
Change in the net actuarial gain/loss
 
 
 (862)
 
Reclassification adjustment for net amortization of actuarial gain/loss included in net income as a component of net periodic cost (benefit)1,357
 1,585
 4,072
 4,878
1,406
 1,250
Total defined-benefit post-retirement benefit plans1,357
 1,585
 4,072
 4,016
1,406
 1,250
Other comprehensive income (loss), before tax9,792
 (101,297) 126,612
 156,386
199,208
 (180,254)
Deferred tax expense (benefit) related to other comprehensive income3,427
 (35,453) 44,314
 54,736
Deferred tax expense (benefit)41,834
 (37,853)
Other comprehensive income (loss), net of tax6,365
 (65,844) 82,298
 101,650
157,374
 (142,401)
Comprehensive income (loss)$99,496
 $14,375
 $345,923
 $322,192
$273,870
 $(35,921)
See Notes to Consolidated Financial Statements.

Cullen/Frost Bankers, Inc.
Consolidated Statements of Changes in Shareholders’ Equity
(Dollars in thousands, except per share amounts)
 Nine Months Ended 
 September 30,
 2017 2016
Total shareholders’ equity at beginning of period$3,002,528
 $2,890,343
Net income263,625
 220,542
Other comprehensive income (loss)82,298
 101,650
Stock option exercises/stock unit conversions (774,799 shares in 2017 and 908,921 shares in 2016)45,422
 47,873
Stock compensation expense recognized in earnings9,013
 7,998
Purchase of treasury stock (1,135,435 shares in 2017)(100,042) 
Cash dividends – preferred stock (approximately $1.01 per share in both 2017 and in 2016)(6,047) (6,047)
Cash dividends – common stock ($1.68 per share in 2017 and $1.61 per share in 2016)(107,754) (100,563)
Total shareholders’ equity at end of period$3,189,043
 $3,161,796
 
Preferred
Stock
 
Common
Stock
 
Additional
Paid-In
Capital
 
Retained
Earnings
 
Accumulated
Other
Comprehensive
Income (Loss),
Net of Tax
 
Treasury
Stock
 Total
Three months ended:             
March 31, 2019             
Balance at beginning of period$144,486
 $642
 $967,304
 $2,440,002
 $(63,600) $(119,917) $3,368,917
Cumulative effect of accounting change
 
 
 (12,611) 
 
 (12,611)
Total shareholders' equity at beginning of period, as adjusted144,486
 642
 967,304
 2,427,391
 (63,600) (119,917) 3,356,306
Net income
 
 
 116,496
 
 
 116,496
Other comprehensive income, net of tax
 
 
 
 157,374
 
 157,374
Stock option exercises/stock unit conversions (100,865 shares)
 
 
 (4,001) 
 8,886
 4,885
Stock-based compensation expense recognized in earnings
 
 3,654
 
 
 
 3,654
Purchase of treasury stock (5,351 shares)
 
 
 
 
 (519) (519)
Cash dividends – preferred stock (approximately $0.34 per share)
 
 
 (2,016) 
 
 (2,016)
Cash dividends – common stock ($0.67 per share)
 
 
 (42,602) 
 
 (42,602)
Balance at end of period$144,486
 $642
 $970,958
 $2,495,268
 $93,774
 $(111,550) $3,593,578
              
March 31, 2018             
Balance at beginning of period$144,486
 $642
 $953,361
 $2,187,069
 $79,512
 $(67,207) $3,297,863
Cumulative effect of accounting change
 
 
 (2,285) 
 
 (2,285)
Total shareholders' equity at beginning of period, as adjusted144,486
 642
 953,361
 2,184,784
 79,512
 (67,207) 3,295,578
Net income
 
 
 106,480
 
 
 106,480
Other comprehensive loss, net of tax
 
 
 
 (142,401) 
 (142,401)
Reclassification of certain income tax effects related to the change in the U.S. statutory federal income tax rate under the Tax Cuts and Jobs Act
 
 
 (9,535) 9,535
 
 
Stock option exercises/stock unit conversions (318,110 shares)
 
 
 (8,861) 
 28,026
 19,165
Stock-based compensation expense recognized in earnings
 
 3,175
 
 
 
 3,175
Cash dividends – preferred stock (approximately $0.34 per share)
 
 
 (2,016) 
 
 (2,016)
Cash dividends – common stock ($0.57 per share)
 
 
 (36,551) 
 
 (36,551)
Balance at end of period$144,486
 $642
 $956,536
 $2,234,301
 $(53,354) $(39,181) $3,243,430

See accompanying Notes to Consolidated Financial Statements.Statements



Cullen/Frost Bankers, Inc.
Consolidated Statements of Cash Flows
(Dollars in thousands)
Nine Months Ended 
 September 30,
Three Months Ended 
 March 31,
2017 20162019 2018
Operating Activities:      
Net income$263,625
 $220,542
$116,496
 $106,480
Adjustments to reconcile net income to net cash from operating activities:      
Provision for loan losses27,358
 42,734
11,003
 6,945
Deferred tax expense (benefit)(9,505) (11,629)(1,044) 10,411
Accretion of loan discounts(11,567) (11,893)(3,757) (3,378)
Securities premium amortization (discount accretion), net66,455
 59,071
28,696
 24,260
Net (gain) loss on securities transactions4,917
 (14,866)
 19
Depreciation and amortization35,819
 35,712
12,752
 12,130
Net (gain) loss on sale/write-down of assets/foreclosed assets(2,045) (373)(4,437) (3,982)
Stock-based compensation9,013
 7,998
3,654
 3,175
Net tax benefit from stock-based compensation5,844
 1,610
716
 2,211
Earnings on life insurance policies(2,367) (2,678)(898) (820)
Net change in:      
Trading account securities(3,018) 418
1,582
 1,326
Lease right-of-use assets4,833
 
Accrued interest receivable and other assets10,495
 11,134
32,634
 23,555
Accrued interest payable and other liabilities(39,580) (2,806)(56,098) 28,376
Net cash from operating activities355,444
 334,974
146,132
 210,708
      
Investing Activities:      
Securities held to maturity:      
Purchases
 

 (1,500)
Sales
 135,610
Maturities, calls and principal repayments780,562
 227,760
23,421
 179,149
Securities available for sale:      
Purchases(9,138,457) (10,079,302)(1,526,279) (3,245,923)
Sales8,993,963
 9,040,245
944,903
 2,984,867
Maturities, calls and principal repayments283,278
 270,737
121,471
 62,768
Proceeds from sale of loans
 30,470
12,699
 
Net change in loans(745,702) (142,698)(322,308) (227,417)
Benefits received on life insurance policies462
 906
Proceeds from sales of premises and equipment1,553
 1,517
4,667
 11,317
Purchases of premises and equipment(23,796) (32,647)(44,039) (16,759)
Proceeds from sales of repossessed properties517
 297

 307
Net cash from investing activities152,380
 (547,105)(785,465) (253,191)
      
Financing Activities:      
Net change in deposits591,694
 763,953
(854,341) (194,611)
Net change in short-term borrowings20,927
 (89,220)(140,399) (115,603)
Proceeds from issuance of subordinated notes98,434
 
Principal payments on subordinated notes(100,000) 
Proceeds from stock option exercises45,422
 47,873
4,885
 19,165
Purchase of treasury stock(100,042) 
(519) 
Cash dividends paid on preferred stock(6,047) (6,047)(2,016) (2,016)
Cash dividends paid on common stock(107,754) (100,563)(42,602) (36,551)
Net cash from financing activities442,634
 615,996
(1,034,992) (329,616)
      
Net change in cash and cash equivalents950,458
 403,865
(1,674,325) (372,099)
Cash and equivalents at beginning of period4,141,445
 3,591,523
Cash and equivalents at end of period$5,091,903
 $3,995,388
Cash and cash equivalents at beginning of period3,955,779
 5,053,047
Cash and cash equivalents at end of period$2,281,454
 $4,680,948


See Notes to Consolidated Financial Statements.

Notes to Consolidated Financial Statements
(Table amounts in thousands, except for share and per share amounts)
Note 1 - Significant Accounting Policies
Nature of Operations. Cullen/Frost Bankers, Inc. (“Cullen/Frost”) is a financial holding company and a bank holding company headquartered in San Antonio, Texas that provides, through its subsidiaries, a broad array of products and services throughout numerous Texas markets. The terms “Cullen/Frost,” “the Corporation,” “we,” “us” and “our” mean Cullen/Frost Bankers, Inc. and its subsidiaries, when appropriate. In addition to general commercial and consumer banking, other products and services offered include trust and investment management, insurance, brokerage, mutual funds, leasing, treasury management, capital markets advisory and item processing.
Basis of Presentation. The consolidated financial statements in this Quarterly Report on Form 10-Q include the accounts of Cullen/Frost and all other entities in which Cullen/Frost has a controlling financial interest. All significant intercompany balances and transactions have been eliminated in consolidation. The accounting and financial reporting policies we follow conform, in all material respects, to accounting principles generally accepted in the United States and to general practices within the financial services industry.
The consolidated financial statements in this Quarterly Report on Form 10-Q have not been audited by an independent registered public accounting firm, but in the opinion of management, reflect all adjustments necessary for a fair presentation of our financial position and results of operations. All such adjustments were of a normal and recurring nature. The consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information and with the instructions to Form 10-Q adopted by the Securities and Exchange Commission (“SEC”). Accordingly, the financial statements do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements and should be read in conjunction with our consolidated financial statements, and notes thereto, for the year ended December 31, 20162018, included in our Annual Report on Form 10-K filed with the SEC on February 3, 20176, 2019 (the “2016“2018 Form 10-K”). Operating results for the interim periods disclosed herein are not necessarily indicative of the results that may be expected for a full year or any future period.
Use of Estimates. The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates. The allowance for loan losses and the fair values of financial instruments and the status of contingencies are particularly subject to change.
Cash Flow Reporting. Additional cash flow information was as follows:
 Three Months Ended 
 March 31,
 2019 2018
Cash paid for interest$34,402
 $13,740
Cash paid for income taxes
 
Significant non-cash transactions:   
Unsettled purchases/sales of securities7,612
 47,723
Loans foreclosed and transferred to other real estate owned and foreclosed assets
 7
Right-of-use lease assets obtained in exchange for lessee operating lease liabilities170,479
 

 Nine Months Ended 
 September 30,
 2017 2016
Cash paid for interest$15,611
 $8,731
Cash paid for income taxes41,969
 39,160
Significant non-cash transactions:   
Unsettled purchases of securities41,763
 54,342
Loans foreclosed and transferred to other real estate owned and foreclosed assets257
 422
Accounting Changes, Reclassifications and Restatements. Certain items in prior financial statements have been reclassified to conform to the current presentation. In addition, as of January 1, 2019, we adopted certain accounting standard updates related to accounting for leases (Topic 842 - Leases), primarily Accounting Standards Update (“ASU”) 2016-02 and subsequent updates. Among other things, these updates require lessees to recognize a lease liability, measured on a discounted basis, related to the lessee's obligation to make lease payments arising under a lease contract; and a right-of-use asset related to the lessee’s right to use, or control the use of, a specified asset for the lease term. The updates did not significantly change lease accounting requirements applicable to lessors and did not significantly impact our financial statements in relation to contracts whereby we act as a lessor. We adopted the updates using a modified-retrospective transition approach and recognized right-of-use lease assets and related lease liabilities totaling $170.5 million and $174.4 million respectively as of January 1, 2019. We elected to apply certain practical adoption expedients provided under the updates whereby we did not reassess (i) whether any expired or existing contracts are or contain leases, (ii) the lease classification for any expired or existing leases and (iii) initial direct costs for any existing leases. We did not elect to apply the recognition requirements of the updates to any short-term leases (as discussed below). As of March 31, 2019, right-of-use lease assets and related lease liabilities totaled $165.5 million and $171.8 million, respectively. Furthermore, during the second quarter of 2019, we expect to recognize an additional right-of-use asset and related lease liability totaling

approximately $110.0 million to $140.0 million in connection with the commencement of the lease of our new corporate headquarters facility in downtown San Antonio. See Note 6 - Commitments and Contingencies.
We lease certain office facilities and office equipment under operating leases. We also own certain office facilities which we lease to outside parties under operating lessor leases; however, such leases are not significant. We do not apply the recognition requirements of Topic 842 - Leases to short-term operating leases. A short-term operating lease has an original term of 12 months or less and does not have a purchase option that is likely to be exercised. For non-short-term operating leases, we recognized lease right-of-use assets and related lease liabilities on our balance sheet upon commencement of the lease in accordance with Topic 842 - Leases. In recognizing lease right-of-use assets and related lease liabilities, we account for lease and non-lease components (such as taxes, insurance, and common area maintenance costs) separately as such amounts are generally readily determinable under our lease contracts. Lease payments over the expected term are discounted using our incremental borrowing rate referenced to the Federal Home Loan Bank Secure Connect advance rates for borrowings of similar term. We also consider renewal and termination options in the determination of the term of the lease. If it is reasonably certain that a renewal or termination option will be exercised, the effects of such options are included in the determination of the expected lease term. Generally, we cannot be reasonably certain about whether or not we will renew a lease until such time the lease is within the last two years of the existing lease term. However, renewal options related to our regional headquarter facilities or operations centers are evaluated on a case-by-case basis, typically in advance of such time frame. When we are reasonably certain that a renewal option will be exercised, we measure/remeasure the right-of-use asset and related lease liability using the lease payments specified for the renewal period or, if such amounts are unspecified, we generally assume an increase (evaluated on a case-by-case basis in light of prevailing market conditions) in the lease payment over the final period of the existing lease term.
We also adopted ASU 2017-08 “Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20) - Premium Amortization on Purchased Callable Debt Securities” as of January 1, 2019. ASU 2017-08 shortens the amortization period for certain callable debt securities held at a premium to require such premiums to be amortized to the earliest call date unless applicable guidance related to certain pools of securities is applied to consider estimated prepayments. Under prior guidance, entities were generally required to amortize premiums on individual, non-pooled callable debt securities as a yield adjustment over the contractual life of the security. ASU 2017-08 does not change the accounting for callable debt securities held at a discount. Upon adoption, using a modified retrospective transition adoption approach, we recognized a cumulative effect reduction to retained earnings totaling$12.6 million. We expect premium amortization expense for 2019 will be approximately $5.2 million higher than what would have been the case had we continued to amortize the affected securities to their respective maturity dates.
Note 2 - Securities
Securities. A summary of the amortized cost and estimated fair value of securities, excluding trading securities, is presented below.
 March 31, 2019 December 31, 2018
 
Amortized
Cost
 
Gross
Unrealized
Gains
 
Gross
Unrealized
Losses
 
Estimated
Fair Value
 
Amortized
Cost
 
Gross
Unrealized
Gains
 
Gross
Unrealized
Losses
 
Estimated
Fair Value
Held to Maturity               
Residential mortgage-backed securities$2,656
 $6
 $53
 $2,609
 $2,737
 $8
 $85
 $2,660
States and political subdivisions1,073,123
 20,628
 2
 1,093,749
 1,101,820
 11,525
 552
 1,112,793
Other1,500
 
 
 1,500
 1,500
 
 
 1,500
Total$1,077,279
 $20,634
 $55
 $1,097,858
 $1,106,057
 $11,533
 $637
 $1,116,953
Available for Sale               
U.S. Treasury$3,455,925
 $5,314
 $16,171
 $3,445,068
 $3,455,417
 $1,772
 $29,500
 $3,427,689
Residential mortgage-backed securities1,210,179
 20,610
 3,354
 1,227,435
 823,208
 13,079
 6,547
 829,740
States and political subdivisions7,130,105
 181,170
 12,549
 7,298,726
 7,089,132
 70,760
 72,690
 7,087,202
Other42,734
 
 
 42,734
 42,690
 
 
 42,690
Total$11,838,943
 $207,094
 $32,074
 $12,013,963
 $11,410,447
 $85,611
 $108,737
 $11,387,321

 September 30, 2017 December 31, 2016
 
Amortized
Cost
 
Gross
Unrealized
Gains
 
Gross
Unrealized
Losses
 
Estimated
Fair Value
 
Amortized
Cost
 
Gross
Unrealized
Gains
 
Gross
Unrealized
Losses
 
Estimated
Fair Value
Held to Maturity               
U.S. Treasury$
 $
 $
 $
 $249,889
 $1,762
 $
 $251,651
Residential mortgage-backed securities3,708
 21
 24
 3,705
 4,511
 39
 
 4,550
States and political subdivisions1,437,164
 36,991
 2,556
 1,471,599
 1,994,710
 16,821
 6,335
 2,005,196
Other1,350
 
 1
 1,349
 1,350
 
 
 1,350
Total$1,442,222
 $37,012
 $2,581
 $1,476,653
 $2,250,460
 $18,622
 $6,335
 $2,262,747
Available for Sale               
U.S. Treasury$3,452,882
 $23,796
 $3,050
 $3,473,628
 $4,003,692
 $24,984
 $8,945
 $4,019,731
Residential mortgage-backed securities658,281
 24,218
 1,304
 681,195
 756,072
 30,388
 1,293
 785,167
States and political subdivisions5,898,098
 130,142
 40,501
 5,987,739
 5,403,918
 50,101
 98,134
 5,355,885
Other42,538
 
 
 42,538
 42,494
 
 
 42,494
Total$10,051,799
 $178,156
 $44,855
 $10,185,100
 $10,206,176
 $105,473
 $108,372
 $10,203,277

All mortgage-backed securities included in the above table were issued by U.S. government agencies and corporations. At September 30, 2017,March 31, 2019, approximately 98.1%98.4% of the securities in our municipal bond portfolio were issued by political subdivisions or agencies within the State of Texas, of which approximately 67.7%68.7% are either guaranteed by the Texas Permanent School Fund, which has a “triple A” insurer financial strength rating, or are secured by U.S. Treasury securities via defeasance of the debt by the issuers. Securities with limited marketability such asand that do not have readily determinable fair values are carried at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for identical or similar securities of the same issuer. These securities include stock in the Federal Reserve Bank and the Federal Home Loan Bank are carried at cost and are reported as other available for sale securities in the table above. The carrying value of securities pledged to secure public funds, trust deposits, repurchase agreements and for other purposes, as required or permitted by law was $3.5$3.4 billion at September 30, 2017March 31, 2019 and $3.9$3.8 billion at December 31, 2016.2018.
During the fourth quarter of 2012, we reclassified certain securities from available for sale to held to maturity. The securities had an aggregate fair value of $2.3 billion with an aggregate net unrealized gain of $165.7 million ($107.7 million, net of tax) on the date of the transfer. The net unamortized, unrealized gain on the remaining transferred securities included in accumulated other comprehensive income in the accompanying balance sheet as of September 30, 2017March 31, 2019 totaled $14.1$2.4 million ($9.21.9 million, net of tax). This amount will be amortized out of accumulated other comprehensive income over the remaining life of the underlying securities as an adjustment of the yield on those securities.
Unrealized Losses. As of September 30, 2017March 31, 2019, securities with unrealized losses, segregated by length of impairment, were as follows:
 Less than 12 Months More than 12 Months Total
 
Estimated
Fair Value
 
Unrealized
Losses
 
Estimated
Fair Value
 
Unrealized
Losses
 
Estimated
Fair Value
 
Unrealized
Losses
Held to Maturity           
Residential mortgage-backed securities$
 $
 $2,039
 $53
 $2,039
 $53
States and political subdivisions
 
 2,361
 2
 2,361
 2
Total$
 $
 $4,400
 $55
 $4,400
 $55
Available for Sale           
U.S. Treasury$
 $
 $3,153,533
 $16,171
 $3,153,533
 $16,171
Residential mortgage-backed securities1,716
 1
 183,952
 3,353
 185,668
 3,354
States and political subdivisions58,884
 1,333
 739,744
 11,216
 798,628
 12,549
Total$60,600
 $1,334
 $4,077,229
 $30,740
 $4,137,829
 $32,074
 Less than 12 Months More than 12 Months Total
 
Estimated
Fair Value
 
Unrealized
Losses
 
Estimated
Fair Value
 
Unrealized
Losses
 
Estimated
Fair Value
 
Unrealized
Losses
Held to Maturity           
Residential mortgage-backed securities$2,212
 $24
 $
 $
 $2,212
 $24
States and political subdivisions5,301
 28
 74,965
 2,528
 80,266
 2,556
Other1,349
 1
 
 
 1,349
 1
Total$8,862
 $53
 $74,965
 $2,528
 $83,827
 $2,581
Available for Sale           
U.S. Treasury$840,074
 $3,050
 $
 $
 $840,074
 $3,050
Residential mortgage-backed securities75,441
 618
 19,458
 686
 94,899
 1,304
States and political subdivisions986,705
 9,713
 842,751
 30,788
 1,829,456
 40,501
Total$1,902,220
 $13,381
 $862,209
 $31,474
 $2,764,429
 $44,855


Declines in the fair value of held-to-maturity and available-for-sale securities below their cost that are deemed to be other than temporary are reflected in earnings as realized losses to the extent the impairment is related to credit losses. The amount of the impairment related to other factors is recognized in other comprehensive income. In estimating other-than-temporary impairment losses, management considers, among other things, (i) the length of time and the extent to which the fair value has been less than cost, (ii) the financial condition and near-term prospects of the issuer, and (iii) the intent and our ability to retain our investment in the issuer for a period of time sufficient to allow for any anticipated recovery in cost.
Management has the ability and intent to hold the securities classified as held to maturity in the table above until they mature, at which time we expect to receive full value for the securities. Furthermore, as of September 30, 2017,March 31, 2019, management does not have the intent to sell any of the securities classified as available for sale in the table above and believes that it is more likely than not that we will not have to sell any such securities before a recovery of cost. Any unrealized losses are due to increases in market interest rates over the yields available at the time the underlying securities were purchased. The fair value is expected to recover as the securities approach their maturity date or repricing date or if market yields for such investments decline. Management does not believe any of the securities are impaired due to reasons of credit quality. Accordingly, as of September 30, 2017March 31, 2019, management believes the impairments detailed in the table above are temporary and no impairment loss has been realized in our consolidated income statement.

Contractual Maturities. The amortized cost and estimated fair value of securities, excluding trading securities, at September 30, 2017March 31, 2019 are presented below by contractual maturity. Expected maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations. Residential mortgage-backed securities and equity securities are shown separately since they are not due at a single maturity date.
 Held to Maturity Available for Sale
 
Amortized
Cost
 
Estimated
Fair Value
 
Amortized
Cost
 
Estimated
Fair Value
Due in one year or less$58,032
��$58,525
 $2,606,267
 $2,593,167
Due after one year through five years128,835
 131,725
 1,662,791
 1,673,779
Due after five years through ten years505,528
 514,331
 375,007
 390,443
Due after ten years382,228
 390,668
 5,941,965
 6,086,405
Residential mortgage-backed securities2,656
 2,609
 1,210,179
 1,227,435
Equity securities
 
 42,734
 42,734
Total$1,077,279
 $1,097,858
 $11,838,943
 $12,013,963

 Held to Maturity Available for Sale
 
Amortized
Cost
 
Estimated
Fair Value
 
Amortized
Cost
 
Estimated
Fair Value
Due in one year or less$251,739
 $256,716
 $37,321
 $38,127
Due after one year through five years116,604
 121,451
 4,056,709
 4,085,795
Due after five years through ten years411,074
 420,160
 385,649
 399,538
Due after ten years659,097
 674,621
 4,871,301
 4,937,907
Residential mortgage-backed securities3,708
 3,705
 658,281
 681,195
Equity securities
 
 42,538
 42,538
Total$1,442,222
 $1,476,653
 $10,051,799
 $10,185,100
Sales of Securities. As more fully discussed in our 2016 Form 10-K, during 2016, we sold certain securities issued by municipalities that, based upon our internal credit analysis, had experienced significant deterioration in creditworthiness. Some of the securities we sold were classified as held to maturity prior to their sale. Despite their classification as held to maturity, we believe the sale of these securities was merited and permissible under the applicable accounting guidelines because of the significant deterioration in the creditworthiness of the issuers.
Sales of securities held to maturity were as follows:
 Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
 2017 2016 2017 2016
Proceeds from sales$
 $
 $
 $135,610
Amortized cost
 
 
 131,840
Gross realized gains
 
 
 3,770
Gross realized losses
 
 
 
Tax (expense) benefit of securities gains/losses
 
 
 (1,319)
Sales of securities available for sale were as follows:
 Three Months Ended 
 March 31,
 2019 2018
Proceeds from sales$944,903
 $2,984,867
Gross realized gains
 
Gross realized losses
 (19)
Tax (expense) benefit of securities gains/losses
 4

 Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
 2017 2016 2017 2016
Proceeds from sales$746,524
 $7,980,049
 $8,993,963
 $9,040,245
Gross realized gains
 1
 
 11,134
Gross realized losses(4,867) (38) (4,917) (38)
Tax (expense) benefit of securities gains/losses1,703
 13
 1,721
 (3,884)

Premiums and Discounts. Premium amortization and discount accretion included in interest income on securities was as follows:
 Three Months Ended 
 March 31,
 2019 2018
Premium amortization$(29,879) $(26,036)
Discount accretion1,183
 1,776
Net (premium amortization) discount accretion$(28,696) $(24,260)

 Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
 2017 2016 2017 2016
Premium amortization$(24,586) $(22,762) $(72,733) $(67,321)
Discount accretion1,783
 2,497
 6,278
 8,250
Net (premium amortization) discount accretion$(22,803) $(20,265) $(66,455) $(59,071)
Trading Account Securities. Trading account securities, at estimated fair value, were as follows:
 March 31,
2019
 December 31,
2018
U.S. Treasury$22,503
 $21,928
States and political subdivisions2,728
 2,158
Total$25,231
 $24,086
 September 30,
2017
 December 31,
2016
U.S. Treasury$18,814
 $16,594
States and political subdivisions907
 109
Total$19,721
 $16,703

Net gains and losses on trading account securities were as follows:
 Three Months Ended 
 March 31,
 2019 2018
Net gain on sales transactions$506
 $505
Net mark-to-market gains (losses)4
 (36)
Net gain (loss) on trading account securities$510
 $469

 Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
 2017 2016 2017 2016
Net gain on sales transactions$414
 $379
 $1,018
 $1,032
Net mark-to-market gains (losses)(8) 
 (51) (1)
Net gain (loss) on trading account securities$406
 $379
 $967
 $1,031

Note 3 - Loans
Loans were as follows:
 March 31,
2019
 
Percentage
of Total
 December 31,
2018
 
Percentage
of Total
Commercial and industrial$5,368,271
 37.3% $5,111,957
 36.3%
Energy:       
Production1,278,366
 8.9
 1,309,314
 9.3
Service166,649
 1.2
 168,775
 1.2
Other114,058
 0.7
 124,509
 0.9
Total energy1,559,073
 10.8
 1,602,598
 11.4
Commercial real estate:       
Commercial mortgages4,256,999
 29.6
 4,121,966
 29.2
Construction1,244,567
 8.6
 1,267,717
 9.0
Land311,629
 2.2
 306,755
 2.2
Total commercial real estate5,813,195
 40.4
 5,696,438
 40.4
Consumer real estate:       
Home equity loans351,762
 2.4
 353,924
 2.5
Home equity lines of credit337,312
 2.3
 337,168
 2.4
Other438,678
 3.1
 427,898
 3.0
Total consumer real estate1,127,752
 7.8
 1,118,990
 7.9
Total real estate6,940,947
 48.2
 6,815,428
 48.3
Consumer and other538,048
 3.7
 569,750
 4.0
Total loans$14,406,339
 100.0% $14,099,733
 100.0%

 September 30,
2017
 
Percentage
of Total
 December 31,
2016
 
Percentage
of Total
Commercial and industrial$4,677,923
 36.8% $4,344,000
 36.3%
Energy:       
Production1,094,927
 8.6
 971,767
 8.1
Service159,893
 1.3
 221,213
 1.8
Other132,240
 1.0
 193,081
 1.7
Total energy1,387,060
 10.9
 1,386,061
 11.6
Commercial real estate:       
Commercial mortgages3,714,172
 29.2
 3,481,157
 29.1
Construction1,082,229
 8.5
 1,043,261
 8.7
Land307,701
 2.4
 311,030
 2.6
Total commercial real estate5,104,102
 40.1
 4,835,448
 40.4
Consumer real estate:       
Home equity loans357,542
 2.8
 345,130
 2.9
Home equity lines of credit288,981
 2.3
 264,862
 2.2
Other367,948
 2.9
 326,793
 2.7
Total consumer real estate1,014,471
 8.0
 936,785
 7.8
Total real estate6,118,573
 48.1
 5,772,233
 48.2
Consumer and other522,748
 4.2
 473,098
 3.9
Total loans$12,706,304
 100.0% $11,975,392
 100.0%
Concentrations of Credit. Most of our lending activity occurs within the State of Texas, including the four largest metropolitan areas of Austin, Dallas/Ft. Worth, Houston and San Antonio, as well as other markets. The majority of our loan portfolio consists of commercial and industrial and commercial real estate loans. As of September 30, 2017,March 31, 2019, there were no concentrations of loans related to any single industry in excess of 10% of total loans other than energy loans, which totaled 10.9%10.8% of total loans. Unfunded commitments to extend credit and standby letters of credit issued to customers in the energy industry totaled $1.1$1.2 billion and $40.9$53.4 million, respectively, as of September 30, 2017.March 31, 2019.

Foreign Loans. We have U.S. dollar denominated loans and commitments to borrowers in Mexico. The outstanding balance of these loans and the unfunded amounts available under these commitments were not significant at September 30, 2017March 31, 2019 or December 31, 2016.2018.
Related Party Loans. In the ordinary course of business, we have granted loans to certain directors, executive officers and their affiliates (collectively referred to as “related parties”). Such loans totaled $272.4 million at March 31, 2019 and $256.1 million at December 31, 2018.
Non-Accrual and Past Due Loans. Non-accrual loans, segregated by class of loans, were as follows:
 March 31,
2019
 December 31,
2018
Commercial and industrial$16,035
 $9,239
Energy45,673
 46,932
Commercial real estate:   
Buildings, land and other26,760
 15,268
Construction410
 
Consumer real estate1,860
 892
Consumer and other1,424
 1,408
Total$92,162
 $73,739

 September 30,
2017
 December 31,
2016
Commercial and industrial$37,239
 $31,475
Energy96,717
 57,571
Commercial real estate:   
Buildings, land and other6,773
 8,550
Construction
 
Consumer real estate2,167
 2,130
Consumer and other208
 425
Total$143,104
 $100,151
As of September 30, 2017, non-accrual loans reported in the table above included $54.1 million related to loans that were restructured as “troubled debt restructurings” during 2017. See the section captioned “Troubled Debt Restructurings” elsewhere in this note. Had non-accrual loans performed in accordance with their original contract terms, we would have recognized additional interest income, net of tax, of approximately $783 thousand and $2.4$1.0 million for the three and nine months ended September 30, 2017,March 31, 2019, compared to $647 thousand and $2.4$1.5 million for the three and nine months ended September 30, 2016.March 31, 2018.

An age analysis of past due loans (including both accruing and non-accruing loans), segregated by class of loans, as of September 30, 2017March 31, 2019 was as follows:
 
Loans
30-89 Days
Past Due
 
Loans
90 or More
Days
Past Due
 
Total
Past Due
Loans
 
Current
Loans
 
Total
Loans
 
Accruing
Loans 90 or
More Days
Past Due
Commercial and industrial$24,572
 $15,675
 $40,247
 $5,328,024
 $5,368,271
 $7,377
Energy10,151
 1,766
 11,917
 1,547,156
 1,559,073
 1,221
Commercial real estate:           
Buildings, land and other22,223
 12,580
 34,803
 4,533,825
 4,568,628
 2,273
Construction6,173
 410
 6,583
 1,237,984
 1,244,567
 
Consumer real estate7,331
 2,207
 9,538
 1,118,214
 1,127,752
 1,794
Consumer and other7,143
 2,532
 9,675
 528,373
 538,048
 1,124
Total$77,593
 $35,170
 $112,763
 $14,293,576
 $14,406,339
 $13,789

 
Loans
30-89 Days
Past Due
 
Loans
90 or More
Days
Past Due
 
Total
Past Due
Loans
 
Current
Loans
 
Total
Loans
 
Accruing
Loans 90 or
More Days
Past Due
Commercial and industrial$26,415
 $30,740
 $57,155
 $4,620,768
 $4,677,923
 $20,614
Energy12,585
 46,097
 58,682
 1,328,378
 1,387,060
 634
Commercial real estate:           
Buildings, land and other9,065
 4,065
 13,130
 4,008,743
 4,021,873
 2,229
Construction
 2,331
 2,331
 1,079,898
 1,082,229
 2,331
Consumer real estate7,671
 2,107
 9,778
 1,004,693
 1,014,471
 835
Consumer and other9,754
 486
 10,240
 512,508
 522,748
 478
Total$65,490
 $85,826
 $151,316
 $12,554,988
 $12,706,304
 $27,121
Impaired Loans. Impaired loans are set forth in the following table. No interest income was recognized on impaired loans subsequent to their classification as impaired.
 
Unpaid Contractual
Principal
Balance
 
Recorded Investment
With No
Allowance
 
Recorded Investment
With
Allowance
 
Total
Recorded
Investment
 
Related
Allowance
March 31, 2019         
Commercial and industrial$15,281
 $3,554
 $10,647
 $14,201
 $6,698
Energy66,754
 6,342
 39,131
 45,473
 8,996
Commercial real estate:      
  
Buildings, land and other27,491
 12,236
 14,086
 26,322
 2,855
Construction430
 410
 
 410
 
Consumer real estate1,285
 1,285
 
 1,285
 
Consumer and other1,492
 
 1,424
 1,424
 1,424
Total$112,733
 $23,827
 $65,288
 $89,115
 $19,973
December 31, 2018         
Commercial and industrial$9,094
 $2,842
 $4,287
 $7,129
 $2,558
Energy67,900
 6,817
 39,890
 46,707
 9,671
Commercial real estate:         
Buildings, land and other15,774
 2,168
 12,517
 14,685
 2,599
Construction
 
 
 
 
Consumer real estate293
 293
 
 293
 
Consumer and other1,475
 
 1,407
 1,407
 1,407
Total$94,536
 $12,120
 $58,101
 $70,221
 $16,235
 
Unpaid Contractual
Principal
Balance
 
Recorded Investment
With No
Allowance
 
Recorded Investment
With
Allowance
 
Total
Recorded
Investment
 
Related
Allowance
September 30, 2017         
Commercial and industrial$48,751
 $31,065
 $3,937
 $35,002
 $1,665
Energy107,883
 34,834
 61,805
 96,639
 13,267
Commercial real estate:      
  
Buildings, land and other9,976
 5,627
 
 5,627
 
Construction
 
 
 
 
Consumer real estate1,214
 1,214
 
 1,214
 
Consumer and other
 
 
 
 
Total$167,824
 $72,740
 $65,742
 $138,482
 $14,932

 Unpaid Contractual
Principal
Balance
 Recorded Investment
With No
Allowance
 Recorded Investment
With
Allowance
 Total
Recorded
Investment
 Related
Allowance
December 31, 2016         
Commercial and industrial$40,288
 $19,862
 $9,047
 $28,909
 $5,436
Energy60,522
 27,759
 29,804
 57,563
 3,750
Commercial real estate:         
Buildings, land and other11,369
 6,866
 
 6,866
 
Construction
 
 
 
 
Consumer real estate977
 655
 
 655
 
Consumer and other32
 30
 
 30
 
Total$113,188
 $55,172
 $38,851
 $94,023
 $9,186

The average recorded investment in impaired loans was as follows:
 Three Months Ended 
 March 31,
 2019
2018
Commercial and industrial$10,665
 $29,496
Energy46,090
 99,657
Commercial real estate:   
Buildings, land and other20,504
 8,009
Construction205
 
Consumer real estate789
 1,321
Consumer and other1,416
 
Total$79,669
 $138,483

 Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
 2017 2016 2017
2016
Commercial and industrial$26,910
 $26,921
 $26,651
 $25,365
Energy76,008
 47,003
 72,055
 57,309
Commercial real estate:       
Buildings, land and other5,553
 8,904
 6,106
 20,444
Construction
 326
 
 548
Consumer real estate1,209
 545
 1,155
 508
Consumer and other
 48
 13
 24
Total$109,680
 $83,747
 $105,980
 $104,198

Troubled Debt Restructurings. Troubled debt restructurings during the ninethree months ended September 30, 2017March 31, 2019 and September 30, 2016March 31, 2018 are set forth in the following table.
 Three Months Ended 
 March 31, 2019
 Three Months Ended 
 March 31, 2018
 
Balance at
Restructure
 
Balance at
Period-End
 
Balance at
Restructure
 
Balance at
Period-End
Commercial and industrial$307
 $293
 $2,203
 $2,171
Energy
 
 13,708
 12,058
Commercial real estate:       
Buildings, land and other5,901
 5,898
 
 
 $6,208
 $6,191
 $15,911
 $14,229
 Nine Months Ended 
 September 30, 2017
 Nine Months Ended 
 September 30, 2016
 
Balance at
Restructure
 
Balance at
Period-End
 
Balance at
Restructure
 
Balance at
Period-End
Commercial and industrial$4,026
 $3,875
 $510
 $505
Energy56,097
 55,023
 73,977
 31,918
Commercial real estate:       
Buildings, land and other
 
 1,455
 1,455
Construction
 
 243
 221
 $60,123
 $58,898
 $76,185
 $34,099

Loan modifications are typically related to extending amortization periods, converting loans to interest only for a limited period of time, deferral of interest payments, waiver of certain covenants, consolidating notes and/or reducing collateral or interest rates. The modifications during the reported periods did not significantly impact our determination of the allowance for loan losses. As
Additional information related to restructured loans as of September 30, 2017, there was one loan totaling $43.1 million that was restructured during the third quarter of 2017 that was in excess of 90 days past due, however, the underlying terms of the modification allowor for the deferral of payments. During the ninethree months ended September 30, 2017, we recognized charge-offs totaling $10.0 million related to loans restructured duringMarch 31, 2019 and March 31, 2018 is set forth in the third and fourth quarters of 2016. During the nine months ended September 30, 2016, we recognized a charge-off of $9.5 million related to a loan restructured during the first quarter of 2016. The loan was subsequently sold with proceeds from the sale totaling $30.5 million.following table.
 March 31, 2019 March 31, 2018
Restructured loans past due in excess of 90 days at period-end:   
Number of loans4
 
Dollar amount of loans$2,367
 $
Restructured loans on non-accrual status at period end2,162
 2,171
Charge-offs of restructured loans:   
Recognized in connection with restructuring
 
Recognized on previously restructured loans
 1,650
Credit Quality Indicators. As part of the on-going monitoring of the credit quality of our loan portfolio, management tracks certain credit quality indicators including trends related to (i) the weighted-average risk grade of commercial loans, (ii) the level of classified commercial loans, (iii) the delinquency status of consumer loans (see details above), (iv) net charge-offs, (v) non-performing loans (see details above) and (vi) the general economic conditions in the State of Texas.
We utilize a risk grading matrix to assign a risk grade to each of our commercial loans. Loans are graded on a scale of 1 to 14. A description of the general characteristics of the 14 risk grades is set forth in our 20162018 Form 10-K. In monitoring credit quality

trends in the context of assessing the appropriate level of the allowance for loan losses, we monitor portfolio credit quality by the weighted-average risk grade of each class of commercial loan. Individual relationship managers review updated financial information for all pass grade loans to reassess the risk grade on at least an annual basis. When a loan has a risk grade of 9, it is still considered a pass grade loan; however, it is considered to be on management’s “watch list,” where a significant risk-modifying action is anticipated in the near term. When a loan has a risk grade of 10 or higher, a special assets officer monitors the loan on an on-going basis.

The following tables present weighted-average risk grades for all commercial loans by class.
 March 31, 2019 December 31, 2018
 Weighted
Average
Risk Grade
 Loans Weighted
Average
Risk Grade
 Loans
Commercial and industrial:       
Risk grades 1-86.08
 $5,024,023
 6.12
 $4,862,275
Risk grade 99.00
 182,286
 9.00
 112,431
Risk grade 1010.00
 51,968
 10.00
 58,328
Risk grade 1111.00
 93,960
 11.00
 69,684
Risk grade 1212.00
 9,336
 12.00
 6,681
Risk grade 1313.00
 6,698
 13.00
 2,558
Total6.33
 $5,368,271
 6.30
 $5,111,957
Energy       
Risk grades 1-85.77
 $1,358,199
 5.76
 $1,451,673
Risk grade 99.00
 81,621
 9.00
 35,565
Risk grade 1010.00
 35,056
 10.00
 43,001
Risk grade 1111.00
 38,524
 11.00
 25,427
Risk grade 1212.00
 36,677
 12.00
 37,261
Risk grade 1313.00
 8,996
 13.00
 9,671
Total6.35
 $1,559,073
 6.22
 $1,602,598
Commercial real estate:  
    
Buildings, land and other       
Risk grades 1-86.78
 $4,280,730
 6.76
 $4,143,264
Risk grade 99.00
 111,496
 9.00
 109,660
Risk grade 1010.00
 62,315
 10.00
 62,353
Risk grade 1111.00
 87,327
 11.00
 98,176
Risk grade 1212.00
 23,905
 12.00
 12,669
Risk grade 1313.00
 2,855
 13.00
 2,599
Total6.99
 $4,568,628
 6.98
 $4,428,721
Construction       
Risk grades 1-87.15
 $1,176,243
 7.13
 $1,177,260
Risk grade 99.00
 49,728
 9.00
 60,754
Risk grade 1010.00
 13,869
 10.00
 24,877
Risk grade 1111.00
 4,317
 11.00
 4,826
Risk grade 1212.00
 410
 12.00
 
Risk grade 1313.00
 
 13.00
 
Total7.27
 $1,244,567
 7.29
 $1,267,717
 September 30, 2017 December 31, 2016
 Weighted
Average
Risk Grade
 Loans Weighted
Average
Risk Grade
 Loans
Commercial and industrial:       
Risk grades 1-86.01
 $4,236,670
 6.01
 $3,989,722
Risk grade 99.00
 201,635
 9.00
 106,988
Risk grade 1010.00
 89,126
 10.00
 115,420
Risk grade 1111.00
 113,253
 11.00
 100,245
Risk grade 1212.00
 35,574
 12.00
 25,939
Risk grade 1313.00
 1,665
 13.00
 5,686
Total6.38
 $4,677,923
 6.35
 $4,344,000
Energy       
Risk grades 1-86.19
 $1,082,349
 6.34
 $854,688
Risk grade 99.00
 46,285
 9.00
 78,524
Risk grade 1010.00
 67,694
 10.00
 150,872
Risk grade 1111.00
 94,015
 11.00
 244,406
Risk grade 1212.00
 83,450
 12.00
 53,821
Risk grade 1313.00
 13,267
 13.00
 3,750
Total7.21
 $1,387,060
 7.95
 $1,386,061
Commercial real estate:  
    
Buildings, land and other       
Risk grades 1-86.69
 $3,720,068
 6.67
 $3,463,064
Risk grade 99.00
 115,196
 9.00
 109,110
Risk grade 1010.00
 110,647
 10.00
 145,067
Risk grade 1111.00
 69,189
 11.00
 66,396
Risk grade 1212.00
 6,773
 12.00
 8,550
Risk grade 1313.00
 
 13.00
 
Total6.93
 $4,021,873
 6.95
 $3,792,187
Construction       
Risk grades 1-87.14
 $1,058,847
 6.97
 $1,023,194
Risk grade 99.00
 18,106
 9.00
 15,829
Risk grade 1010.00
 3,768
 10.00
 2,889
Risk grade 1111.00
 1,508
 11.00
 1,349
Risk grade 1212.00
 
 12.00
 
Risk grade 1313.00
 
 13.00
 
Total7.19
 $1,082,229
 7.01
 $1,043,261


Net (charge-offs)/recoveries, segregated by class of loans, were as follows:
 Three Months Ended 
 March 31,
 2019 2018
Commercial and industrial$(1,938) $(7,675)
Energy47
 (2,849)
Commercial real estate:   
Buildings, land and other27
 81
Construction3
 2
Consumer real estate(1,689) (526)
Consumer and other(3,235) (1,457)
Total$(6,785) $(12,424)

 Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
 2017 2016 2017 2016
Commercial and industrial$(4,565) $(3,079) $(12,155) $(8,177)
Energy451
 (865) (10,010) (18,623)
Commercial real estate:       
Buildings, land and other266
 259
 768
 801
Construction2
 9
 8
 18
Consumer real estate(629) (195) (422) (22)
Consumer and other(1,760) (1,115) (4,289) (2,817)
Total$(6,235) $(4,986) $(26,100) $(28,820)

In assessing the general economic conditions in the State of Texas, management monitors and tracks the Texas Leading Index (“TLI”), which is produced by the Federal Reserve Bank of Dallas. The TLI, the components of which are more fully described in our 20162018 Form 10-K, totaled 124.6127.3 at AugustMarch 31, 2017 (most recent date available)2019 and 123.1125.6 at December 31, 2016.2018. A higher TLI value implies more favorable economic conditions.
Allowance for Loan Losses. The allowance for loan losses is a reserve established through a provision for loan losses charged to expense, which represents management’s best estimate of inherent losses that have been incurred within the existing portfolio of loans. The allowance, in the judgment of management, is necessary to reserve for estimated loan losses and risks inherent in the loan portfolio. Our allowance for loan loss methodology, which is more fully described in our 20162018 Form 10-K, follows the accounting guidance set forth in U.S. generally accepted accounting principles and the Interagency Policy Statement on the Allowance for Loan and Lease Losses, which was jointly issued by U.S. bank regulatory agencies. The level of the allowance reflects management’s continuing evaluation of industry concentrations, specific credit risks, loan loss and recovery experience, current loan portfolio quality, present economic, political and regulatory conditions and unidentified losses inherent in the current loan portfolio. Portions of the allowance may be allocated for specific credits; however, the entire allowance is available for any credit that, in management’s judgment, should be charged off.
The following table presents details of the allowance for loan losses allocated to each portfolio segment as of September 30, 2017March 31, 2019 and December 31, 20162018 and detailed on the basis of the impairment evaluation methodology we used:
 
Commercial
and
Industrial
 Energy 
Commercial
Real Estate
 
Consumer
Real Estate
 
Consumer
and Other
 Total
March 31, 2019           
Historical valuation allowances$31,431
 $9,293
 $20,576
 $2,571
 $7,699
 $71,570
Specific valuation allowances6,698
 8,996
 2,855
 
 1,424
 19,973
General valuation allowances10,870
 4,200
 3,812
 1,654
 (84) 20,452
Macroeconomic valuation allowances9,572
 2,854
 9,212
 1,436
 1,281
 24,355
Total$58,571
 $25,343
 $36,455
 $5,661
 $10,320
 $136,350
Allocated to loans:           
Individually evaluated$6,698
 $8,996
 $2,855
 $
 $1,424
 $19,973
Collectively evaluated51,873
 16,347
 33,600
 5,661
 8,896
 116,377
Total$58,571
 $25,343
 $36,455
 $5,661
 $10,320
 $136,350
December 31, 2018           
Historical valuation allowances$25,351
 $9,697
 $20,817
 $2,688
 $6,845
 $65,398
Specific valuation allowances2,558
 9,671
 2,599
 
 1,407
 16,235
General valuation allowances10,062
 6,014
 4,366
 1,671
 (13) 22,100
Macroeconomic valuation allowances10,609
 3,670
 10,995
 1,744
 1,381
 28,399
Total$48,580
 $29,052
 $38,777
 $6,103
 $9,620
 $132,132
Allocated to loans:           
Individually evaluated$2,558
 $9,671
 $2,599
 $
 $1,407
 $16,235
Collectively evaluated46,022
 19,381
 36,178
 6,103
 8,213
 115,897
Total$48,580
 $29,052
 $38,777
 $6,103
 $9,620
 $132,132
 
Commercial
and
Industrial
 Energy 
Commercial
Real Estate
 
Consumer
Real Estate
 
Consumer
and Other
 Total
September 30, 2017           
Historical valuation allowances$27,190
 $21,900
 $18,304
 $2,443
 $5,491
 $75,328
Specific valuation allowances1,665
 13,267
 
 
 
 14,932
General valuation allowances7,397
 4,677
 4,841
 2,040
 163
 19,118
Macroeconomic valuation allowances12,185
 12,069
 14,930
 2,392
 3,349
 44,925
Total$48,437
 $51,913
 $38,075
 $6,875
 $9,003
 $154,303
Allocated to loans:           
Individually evaluated$1,665
 $13,267
 $
 $
 $
 $14,932
Collectively evaluated46,772
 38,646
 38,075
 6,875
 9,003
 139,371
Total$48,437
 $51,913
 $38,075
 $6,875
 $9,003
 $154,303
December 31, 2016           
Historical valuation allowances$33,251
 $34,626
 $16,976
 $2,225
 $4,585
 $91,663
Specific valuation allowances5,436
 3,750
 
 
 
 9,186
General valuation allowances6,708
 3,769
 5,004
 1,506
 (144) 16,843
Macroeconomic valuation allowances7,520
 18,508
 8,233
 507
 585
 35,353
Total$52,915
 $60,653
 $30,213
 $4,238
 $5,026
 $153,045
Allocated to loans:           
Individually evaluated$5,436
 $3,750
 $
 $
 $
 $9,186
Collectively evaluated47,479
 56,903
 30,213
 4,238
 5,026
 143,859
Total$52,915
 $60,653
 $30,213
 $4,238
 $5,026
 $153,045


Our recorded investment in loans as of September 30, 2017March 31, 2019 and December 31, 20162018 related to each balance in the allowance for loan losses by portfolio segment and detailed on the basis of the impairment methodology we used was as follows:
 
Commercial
and
Industrial
 Energy Commercial
Real Estate
 Consumer
Real Estate
 Consumer
and Other
 Total
March 31, 2019           
Individually evaluated$14,201
 $45,473
 $26,732
 $1,285
 $1,424
 $89,115
Collectively evaluated5,354,070
 1,513,600
 5,786,463
 1,126,467
 536,624
 14,317,224
Total$5,368,271
 $1,559,073
 $5,813,195
 $1,127,752
 $538,048
 $14,406,339
December 31, 2018           
Individually evaluated$7,129
 $46,707
 $14,685
 $293
 $1,407
 $70,221
Collectively evaluated5,104,828
 1,555,891
 5,681,753
 1,118,697
 568,343
 14,029,512
Total$5,111,957
 $1,602,598
 $5,696,438
 $1,118,990
 $569,750
 $14,099,733

 
Commercial
and
Industrial
 Energy Commercial
Real Estate
 Consumer
Real Estate
 Consumer
and Other
 Total
September 30, 2017           
Individually evaluated$35,002
 $96,639
 $5,627
 $1,214
 $
 $138,482
Collectively evaluated4,642,921
 1,290,421
 5,098,475
 1,013,257
 522,748
 12,567,822
Total$4,677,923
 $1,387,060
 $5,104,102
 $1,014,471
 $522,748
 $12,706,304
December 31, 2016           
Individually evaluated$28,909
 $57,563
 $6,866
 $655
 $30
 $94,023
Collectively evaluated4,315,091
 1,328,498
 4,828,582
 936,130
 473,068
 11,881,369
Total$4,344,000
 $1,386,061
 $4,835,448
 $936,785
 $473,098
 $11,975,392
The following table details activity in the allowance for loan losses by portfolio segment for the three and nine months ended September 30, 2017March 31, 2019 and 20162018. Allocation of a portion of the allowance to one category of loans does not preclude its availability to absorb losses in other categories.
 
Commercial
and
Industrial
 Energy 
Commercial
Real Estate
 
Consumer
Real Estate
 
Consumer
and Other
 Total
Three months ended:           
March 31, 2019           
Beginning balance$48,580
 $29,052
 $38,777
 $6,103
 $9,620
 $132,132
Provision for loan losses11,929
 (3,756) (2,352) 1,247
 3,935
 11,003
Charge-offs(2,688) 
 (60) (1,778) (5,697) (10,223)
Recoveries750
 47
 90
 89
 2,462
 3,438
Net charge-offs(1,938) 47
 30
 (1,689) (3,235) (6,785)
Ending balance$58,571
 $25,343
 $36,455
 $5,661
 $10,320
 $136,350
March 31, 2018           
Beginning balance$59,614
 $51,528
 $30,948
 $5,657
 $7,617
 $155,364
Provision for loan losses5,794
 (9,640) 7,443
 1,218
 2,130
 6,945
Charge-offs(9,252) (2,850) (5) (719) (3,972) (16,798)
Recoveries1,577
 1
 88
 193
 2,515
 4,374
Net charge-offs(7,675) (2,849) 83
 (526) (1,457) (12,424)
Ending balance$57,733
 $39,039
 $38,474
 $6,349
 $8,290
 $149,885

 
Commercial
and
Industrial
 Energy 
Commercial
Real Estate
 
Consumer
Real Estate
 
Consumer
and Other
 Total
Three months ended:           
September 30, 2017           
Beginning balance$48,906
 $54,277
 $33,002
 $5,535
 $7,838
 $149,558
Provision for loan losses4,096
 (2,815) 4,805
 1,969
 2,925
 10,980
Charge-offs(5,468) 
 
 (766) (4,120) (10,354)
Recoveries903
 451
 268
 137
 2,360
 4,119
Net charge-offs(4,565) 451
 268
 (629) (1,760) (6,235)
Ending balance$48,437
 $51,913
 $38,075
 $6,875
 $9,003
 $154,303
September 30, 2016           
Beginning balance$47,578
 $66,339
 $27,063
 $3,935
 $4,799
 $149,714
Provision for loan losses4,632
 (3,231) 1,886
 427
 1,331
 5,045
Charge-offs(4,036) (884) (9) (287) (3,300) (8,516)
Recoveries957
 19
 277
 92
 2,185
 3,530
Net charge-offs(3,079) (865) 268
 (195) (1,115) (4,986)
Ending balance$49,131
 $62,243
 $29,217
 $4,167
 $5,015
 $149,773
            
Nine months ended:           
September 30, 2017           
Beginning balance$52,915
 $60,653
 $30,213
 $4,238
 $5,026
 $153,045
Provision for loan losses7,677
 1,270
 7,086
 3,059
 8,266
 27,358
Charge-offs(14,574) (10,595) (14) (779) (11,291) (37,253)
Recoveries2,419
 585
 790
 357
 7,002
 11,153
Net charge-offs(12,155) (10,010) 776
 (422) (4,289) (26,100)
Ending balance$48,437
 $51,913
 $38,075
 $6,875
 $9,003
 $154,303
September 30, 2016           
Beginning balance$42,993
 $54,696
 $24,313
 $4,659
 $9,198
 $135,859
Provision for loan losses14,315
 26,170
 4,085
 (470) (1,366) 42,734
Charge-offs(10,754) (18,644) (56) (464) (9,276) (39,194)
Recoveries2,577
 21
 875
 442
 6,459
 10,374
Net charge-offs(8,177) (18,623) 819
 (22) (2,817) (28,820)
Ending balance$49,131
 $62,243
 $29,217
 $4,167
 $5,015
 $149,773

Note 4 - Goodwill and Other Intangible Assets
Goodwill and other intangible assets are presented in the table below.
September 30,
2017
 December 31,
2016
March 31,
2019
 December 31,
2018
Goodwill$654,952
 $654,952
$654,952
 $654,952
Other intangible assets:      
Core deposits$4,340
 $5,298
$2,705
 $2,959
Customer relationships1,086
 1,410
606
 672
Non-compete agreements49
 68
13
 18
$5,475
 $6,776
$3,324
 $3,649

The estimated aggregate future amortization expense for intangible assets remaining as of September 30, 2017March 31, 2019 is as follows:
Remainder of 2019$842
2020919
2021697
2022481
2023283
Thereafter102
 $3,324
Remainder of 2017$402
20181,424
20191,167
2020918
2021697
Thereafter867
 $5,475

Note 5 - Deposits
Deposits were as follows:
 March 31,
2019
 
Percentage
of Total
 December 31,
2018
 
Percentage
of Total
Non-interest-bearing demand deposits:     
Commercial and individual$9,621,070
 36.6% $10,305,850
 37.9%
Correspondent banks197,784
 0.7
 235,748
 0.9
Public funds310,054
 1.2
 455,896
 1.7
Total non-interest-bearing demand deposits10,128,908
 38.5
 10,997,494
 40.5
Interest-bearing deposits:       
Private accounts:       
Savings and interest checking6,975,228
 26.5
 6,977,813
 25.7
Money market accounts7,755,793
 29.5
 7,777,470
 28.6
Time accounts of $100,000 or more592,708
 2.3
 526,789
 2.0
Time accounts under $100,000340,405
 1.3
 331,511
 1.2
Total private accounts15,664,134
 59.6
 15,613,583
 57.5
Public funds:       
Savings and interest checking428,420
 1.6
 473,754
 1.8
Money market accounts69,245
 0.3
 59,953
 0.2
Time accounts of $100,000 or more4,068
 
 4,332
 
Time accounts under $100,00088
 
 88
 
Total public funds501,821
 1.9
 538,127
 2.0
Total interest-bearing deposits16,165,955
 61.5
 16,151,710
 59.5
Total deposits$26,294,863
 100.0% $27,149,204
 100.0%
 September 30,
2017
 
Percentage
of Total
 December 31,
2016
 
Percentage
of Total
Non-interest-bearing demand deposits:     
Commercial and individual$10,466,844
 39.6% $9,670,989
 37.5%
Correspondent banks226,313
 0.9
 280,751
 1.1
Public funds481,094
 1.8
 561,629
 2.2
Total non-interest-bearing demand deposits11,174,251
 42.3
 10,513,369
 40.8
Interest-bearing deposits:       
Private accounts:       
Savings and interest checking6,449,079
 24.4
 6,436,065
 24.9
Money market accounts7,607,675
 28.8
 7,486,431
 29.0
Time accounts of $100,000 or more454,096
 1.7
 460,028
 1.8
Time accounts under $100,000323,748
 1.3
 338,714
 1.3
Total private accounts14,834,598
 56.2
 14,721,238
 57.0
Public funds:       
Savings and interest checking312,430
 1.2
 446,872
 1.7
Money market accounts68,018
 0.3
 113,669
 0.4
Time accounts of $100,000 or more13,462
 
 15,748
 0.1
Time accounts under $100,000510
 
 679
 
Total public funds394,420
 1.5
 576,968
 2.2
Total interest-bearing deposits15,229,018
 57.7
 15,298,206
 59.2
Total deposits$26,403,269
 100.0% $25,811,575
 100.0%

The following table presents additional information about our deposits:
 March 31,
2019
 December 31,
2018
Deposits from foreign sources (primarily Mexico)$761,685
 $752,658
Deposits not covered by deposit insurance12,116,569
 13,111,210
 September 30,
2017
 December 31,
2016
Deposits from foreign sources (primarily Mexico)$756,326
 $776,003
Deposits not covered by deposit insurance13,255,165
 12,889,047

Note 6 - Borrowed Funds
Subordinated Notes Payable. In March 2017, we issued $100 million of 4.50% subordinated notes that mature on March 17, 2027. The notes, which qualify as Tier 2 capital for Cullen/Frost, bear interest at the rate of 4.50% per annum, payable semi-annually on each March 17 and September 17. The notes are unsecured and subordinated in right of payment to the payment of our existing and future senior indebtedness and structurally subordinated to all existing and future indebtedness of our subsidiaries. Unamortized debt issuance costs related to these notes, totaled approximately $1.5 million at September 30, 2017. Proceeds from sale of the notes were used for general corporate purposes.
Our $100 million of 5.75% fixed-to-floating rate subordinated notes matured and were redeemed on February 15, 2017. See Note 8 - Borrowed Funds in our 2016 Form 10-K for additional information about these notes.
Note 76 - Commitments and Contingencies
Financial Instruments with Off-Balance-Sheet Risk. In the normal course of business, we enter into various transactions, which, in accordance with generally accepted accounting principles are not included in our consolidated balance sheets. We enter into these transactions to meet the financing needs of our customers. As more fully discussed in our 20162018 Form 10-K, these transactions include commitments to extend credit and standby letters of credit, which involve, to varying degrees, elements of credit risk and interest rate risk in excess of the amounts recognized in the consolidated balance sheets. We minimize our exposure to loss under these commitments by subjecting them to credit approval and monitoring procedures.
Financial instruments with off-balance-sheet risk were as follows:
 March 31,
2019
 December 31,
2018
Commitments to extend credit$8,522,497
 $8,369,721
Standby letters of credit275,923
 271,575
Deferred standby letter of credit fees1,816
 2,069

 September 30,
2017
 December 31,
2016
Commitments to extend credit$7,939,438
 $7,476,420
Standby letters of credit236,996
 239,482
Deferred standby letter of credit fees1,860
 2,054

Lease Commitments. We lease certain office facilities and office equipment under operating leases. Rent expense for all operating leases totaled $7.7$8.6 million and $23.0$8.2 million during the three and nine months ended September 30, 2017March 31, 2019 and $7.5March 31, 2018, respectively. On January 1, 2019, we adopted a new accounting standard which required the recognition of our operating leases on our balance sheet. See Note 1 - Significant Accounting Policies. As of March 31, 2019, right-of-use lease assets and related lease liabilities totaled $165.5 million and $22.0$171.8 million, respectively, and are included with premises and equipment and accrued interest payable and other liabilities, respectively, on our accompanying consolidated balance sheet. Furthermore, during the threesecond quarter of 2019, we expect to recognize an additional right-of-use lessee lease asset and nine months ended September 30, 2016.related lessee lease liability totaling approximately $110.0 million to $140.0 million in connection with the commencement of the lease of our new corporate headquarters facility in downtown San Antonio. There has been no significant change in our expected future minimum lease payments since December 31, 2016.2018. See the 20162018 Form 10-K for information regarding these commitments.
Litigation.Litigation. We are subject to various claims and legal actions that have arisen in the course of conducting business. Management does not expect the ultimate disposition of these matters to have a material adverse impact on our financial statements.
Note 87 - Capital and Regulatory Matters
Banks and bank holding companies are subject to various regulatory capital requirements administered by state and federal banking agencies. Capital adequacy guidelines and, additionally for banks, prompt corrective action regulations, involve quantitative measures of assets, liabilities, and certain off-balance-sheet items calculated under regulatory accounting practices. Capital amounts and classifications are also subject to qualitative judgments by regulators about components, risk weighting and other factors.
Cullen/Frost’s and Frost Bank’s Common Equity Tier 1 capital includes common stock and related paid-in capital, net of treasury stock, and retained earnings. In connection with the adoption of the Basel III Capital Rules, we elected to opt-out of the requirement to include most components of accumulated other comprehensive income in Common Equity Tier 1. Common Equity Tier 1 for both Cullen/Frost and Frost Bank is reduced by goodwill and other intangible assets, net of associated deferred tax liabilities, and subject to transition provisions. Frost Bank's Common Equity Tier 1 is also reduced by its equity investment in its financial subsidiary, Frost Insurance Agency (“FIA”).
Tier 1 capital includes Common Equity Tier 1 capital and additional Tier 1 capital. For Cullen/Frost, additional Tier 1 capital at September 30, 2017March 31, 2019 and December 31, 20162018 includes $144.5 million of 5.375% non-cumulative perpetual preferred stock. Frost Bank did not have any additional Tier 1 capital beyond Common Equity Tier 1 at September 30, 2017March 31, 2019 or December 31, 2016.2018.
Total capital includes Tier 1 capital and Tier 2 capital. Tier 2 capital for both Cullen/Frost and Frost Bank includes a permissible portion of the allowance for loan losses. Tier 2 capital for Cullen/Frost also includes $100.0 million of qualified subordinated debt at September 30, 2017 and $133.0 million of trust preferred securities at both September 30, 2017March 31, 2019 and December 31, 2016.2018.

The following table presentstables present actual and required capital ratios as of March 31, 2019 and December 31, 2018 for Cullen/Frost and Frost Bank under the Basel III Capital Rules. The Basel III Capital Rules became fully phased-in on January 1, 2019. The minimum required capital amounts presented as of December 31, 2018 include the minimum required capital levels applicable as of September 30, 2017 and December 31, 2016 based on the phase-in provisions of the Basel III Capital Rules andthat date as well as the minimum required capital levels as of January 1, 2019 when the Basel III Capital Rules have beenbecame fully phased-in. Capital levels required to be considered well capitalized are based upon prompt corrective action regulations, as amended to reflect the changes under the Basel III Capital Rules. See the 20162018 Form 10-K for a more detailed discussion of the Basel III Capital Rules. After a review of risk-weight classifications during the first quarter of 2019, risk-weightings for certain loans were reclassified. Amounts reported as of December 31, 2018 have been revised to reflect these reclassifications.
 Actual Minimum Capital Required - Basel III Required to be
Considered Well
Capitalized
 Capital
Amount
 Ratio Capital
Amount
 Ratio Capital
Amount
 Ratio
March 31, 2019           
Common Equity Tier 1 to Risk-Weighted Assets           
Cullen/Frost$2,710,546
 12.34% $1,537,237
 7.00% $1,427,434
 6.50%
Frost Bank2,784,786
 12.71
 1,533,226
 7.00
 1,423,709
 6.50
Tier 1 Capital to Risk-Weighted Assets           
Cullen/Frost2,855,032
 13.00
 1,866,645
 8.50
 1,756,842
 8.00
Frost Bank2,784,786
 12.71
 1,861,774
 8.50
 1,752,258
 8.00
Total Capital to Risk-Weighted Assets           
Cullen/Frost3,224,882
 14.68
 2,305,856
 10.50
 2,196,053
 10.00
Frost Bank2,921,636
 13.34
 2,299,838
 10.50
 2,190,322
 10.00
Leverage Ratio           
Cullen/Frost2,855,032
 9.35
 1,221,268
 4.00
 1,526,584
 5.00
Frost Bank2,784,786
 9.13
 1,220,083
 4.00
 1,525,104
 5.00
Actual Minimum Capital Required - Basel III Phase-In Schedule Minimum Capital Required - Basel III Fully Phased-In 
Required to be
Considered Well
Capitalized
Actual Minimum Capital Required - Basel III Phase-In Schedule 
Minimum Capital Required - Basel III
Fully Phased-In
 Required to be
Considered Well
Capitalized
Capital
Amount
 Ratio 
Capital
Amount
 Ratio 
Capital
Amount
 Ratio 
Capital
Amount
 RatioCapital
Amount
 Ratio Capital
Amount
 Ratio Capital
Amount
 Ratio Capital
Amount
 Ratio
September 30, 2017               
December 31, 2018               
Common Equity Tier 1 to Risk-Weighted Assets                              
Cullen/Frost$2,345,433
 12.38% $1,089,289
 5.75% $1,326,014
 7.00% $1,231,370
 6.50%$2,642,475
 12.27% $1,372,573
 6.375% $1,507,139
 7.00% $1,358,171
 6.50%
Frost Bank2,461,004
 13.02
 1,086,527
 5.75
 1,322,652
 7.00
 1,228,248
 6.50
2,743,973
 12.78
 1,368,701
 6.375
 1,502,887
 7.00
 1,354,222
 6.50
Tier 1 Capital to Risk-Weighted Assets                              
Cullen/Frost2,489,919
 13.14
 1,373,451
 7.25
 1,610,160
 8.50
 1,515,532
 8.00
2,786,961
 12.94
 1,695,532
 7.875
 1,830,098
 8.50
 1,671,595
 8.00
Frost Bank2,461,004
 13.02
 1,369,969
 7.25
 1,606,077
 8.50
 1,511,690
 8.00
2,743,973
 12.78
 1,690,748
 7.875
 1,824,934
 8.50
 1,666,735
 8.00
Total Capital to Risk-Weighted Assets                              
Cullen/Frost2,877,222
 15.19
 1,752,334
 9.25
 1,989,021
 10.50
 1,894,415
 10.00
3,152,593
 14.64
 2,126,143
 9.875
 2,260,709
 10.50
 2,089,494
 10.00
Frost Bank2,615,307
 13.84
 1,747,891
 9.25
 1,983,978
 10.50
 1,889,612
 10.00
2,876,605
 13.40
 2,120,144
 9.875
 2,254,331
 10.50
 2,083,419
 10.00
Leverage Ratio                              
Cullen/Frost2,489,919
 8.39
 1,187,616
 4.00
 1,187,573
 4.00
 1,484,521
 5.00
2,786,961
 9.06
 1,231,028
 4.00
 1,231,028
 4.00
 1,538,785
 5.00
Frost Bank2,461,004
 8.29
 1,186,763
 4.00
 1,186,719
 4.00
 1,483,453
 5.00
2,743,973
 8.93
 1,229,650
 4.00
 1,229,650
 4.00
 1,537,062
 5.00
December 31, 2016               
Common Equity Tier 1 to Risk-Weighted Assets               
Cullen/Frost$2,239,186
 12.52% $916,360
 5.125% $1,251,425
 7.00% $1,162,213
 6.50%
Frost Bank2,296,480
 12.88
 913,460
 5.125
 1,247,463
 7.00
 1,158,535
 6.50
Tier 1 Capital to Risk-Weighted Assets               
Cullen/Frost2,383,672
 13.33
 1,184,563
 6.625
 1,519,587
 8.50
 1,430,416
 8.00
Frost Bank2,296,480
 12.88
 1,180,814
 6.625
 1,514,776
 8.50
 1,425,889
 8.00
Total Capital to Risk-Weighted Assets               
Cullen/Frost2,669,717
 14.93
 1,542,168
 8.625
 1,877,137
 10.50
 1,788,020
 10.00
Frost Bank2,449,525
 13.74
 1,537,286
 8.625
 1,871,194
 10.50
 1,782,361
 10.00
Leverage Ratio               
Cullen/Frost2,383,672
 8.14
 1,171,682
 4.00
 1,171,573
 4.00
 1,464,602
 5.00
Frost Bank2,296,480
 7.85
 1,170,249
 4.00
 1,170,141
 4.00
 1,462,812
 5.00

As of September 30, 2017,March 31, 2019, capital levels at Cullen/Frost and Frost Bank exceed all capital adequacy requirements under the fully phased-in Basel III Capital Rules on a fully phased-in basis.Rules. Based on the ratios presented above, capital levels as of September 30, 2017March 31, 2019 at Cullen/Frost and Frost Bank exceed the minimum levels necessary to be considered “well capitalized.”
Cullen/Frost and Frost Bank are subject to the regulatory capital requirements administered by the Federal Reserve Board and, for Frost Bank, the Federal Deposit Insurance Corporation (“FDIC”). Regulatory authorities can initiate certain mandatory actions if Cullen/Frost or Frost Bank fail to meet the minimum capital requirements, which could have a direct material effect on our financial statements. Management believes, as of September 30, 2017March 31, 2019, that Cullen/Frost and Frost Bank meet all capital adequacy requirements to which they are subject.

Stock Repurchase Plans. From time to time, our board of directors has authorized stock repurchase plans. In general, stock repurchase plans allow us to proactively manage our capital position and return excess capital to shareholders. Shares purchased under such plans also provide us with shares of common stock necessary to satisfy obligations related to stock compensation awards. On October 27, 2016,24, 2017, our board of directors authorized a $100.0$150.0 million stock repurchase program, allowing us to

repurchase shares of our common stock over a two-yeartwo year period from time to time at various prices in the open market or through private transactions. DuringNo shares were repurchased under this plan during the three months ended September 30, 2017,first quarter 2019 while we repurchased 1,134,9661,027,292 shares under the plan at at a total cost of $100.0 million.million during the fourth quarter of 2018. Under the Basel III Capital Rules, Cullen/Frost may not repurchase its common stock (or repurchase or redeem any of its preferred stock or subordinated notes) without the prior approval of the Federal Reserve Board.
Dividend Restrictions. In the ordinary course of business, Cullen/Frost is dependent upon dividends from Frost Bank to provide funds for the payment of dividends to shareholders and to provide for other cash requirements.requirements, including to repurchase its common stock. Banking regulations may limit the amount of dividends that may be paid. Approval by regulatory authorities is required if the effect of dividends declared would cause the regulatory capital of Frost Bank to fall below specified minimum levels. Approval is also required if dividends declared exceed the net profits for that year combined with the retained net profits for the preceding two years. Under the foregoing dividend restrictions and while maintaining its “well capitalized” status, at September 30, 2017,March 31, 2019, Frost Bank could pay aggregate dividends of up to $480.2$521.5 million to Cullen/Frost without prior regulatory approval.
Under the terms of the junior subordinated deferrable interest debentures that Cullen/Frost has issued to Cullen/Frost Capital Trust II and WNB Capital Trust I, Cullen/Frost has the right at any time during the term of the debentures to defer the payment of interest at any time or from time to time for an extension period not exceeding 20 consecutive quarterly periods with respect to each extension period. In the event that we have elected to defer interest on the debentures, we may not, with certain exceptions, declare or pay any dividends or distributions on our capital stock or purchase or acquire any of our capital stock.
Under the terms of our Series A Preferred Stock, in the event that we do not declare and pay dividends on our Series A Preferred Stock for the most recent dividend period, we may not, with certain exceptions, declare or pay dividends on, or purchase, redeem or otherwise acquire, shares of our common stock or any of our securities that rank junior to our Series A Preferred Stock.

Note 98 - Derivative Financial Instruments
The fair value of derivative positions outstanding is included in accrued interest receivable and other assets and accrued interest payable and other liabilities in the accompanying consolidated balance sheets and in the net change in each of these financial statement line items in the accompanying consolidated statements of cash flows.
Interest Rate Derivatives. We utilize interest rate swaps, caps and floors to mitigate exposure to interest rate risk and to facilitate the needs of our customers. Our objectives for utilizing these derivative instruments are described in our 20162018 Form 10-K.
The notional amounts and estimated fair values of interest rate derivative contracts are presented in the following table. The fair values of interest rate derivative contracts are estimated utilizing internal valuation models with observable market data inputs, or as determined by the Chicago Mercantile Exchange (“CME”) for centrally cleared derivative contracts. Beginning in 2017, CME rules legally characterize variation margin payments for centrally cleared derivatives as settlements of the derivatives' exposure rather than collateral. As a result, the variation margin payment and the related derivative instruments are considered a single unit of account for accounting and financial reporting purposes. Variation margin, as determined by the CME, is settled daily. As a result, derivative contracts that clear through the CME have an estimated fair value of zero as of September 30, 2017.March 31, 2019 and December 31, 2018.
 March 31, 2019 December 31, 2018
 
Notional
Amount
 
Estimated
Fair Value
 
Notional
Amount
 
Estimated
Fair Value
Derivatives designated as hedges of fair value:       
Financial institution counterparties:       
Loan/lease interest rate swaps – assets$10,642
 $141
 $10,941
 $207
Loan/lease interest rate swaps – liabilities3,538
 (185) 3,885
 (199)
Non-hedging interest rate derivatives:       
Financial institution counterparties:       
Loan/lease interest rate swaps – assets363,454
 1,343
 496,887
 2,384
Loan/lease interest rate swaps – liabilities748,152
 (12,868) 691,143
 (8,921)
Loan/lease interest rate caps – assets143,084
 688
 122,791
 509
Customer counterparties:       
Loan/lease interest rate swaps – assets764,546
 24,818
 691,143
 16,706
Loan/lease interest rate swaps – liabilities347,060
 (3,503) 496,887
 (8,891)
Loan/lease interest rate caps – liabilities143,084
 (688) 122,791
 (509)

 September 30, 2017 December 31, 2016
 
Notional
Amount
 
Estimated
Fair Value
 
Notional
Amount
 
Estimated
Fair Value
Derivatives designated as hedges of fair value:       
Financial institution counterparties:       
Loan/lease interest rate swaps – assets$39,372
 $296
 $41,818
 $368
Loan/lease interest rate swaps – liabilities14,077
 (764) 18,812
 (1,278)
Non-hedging interest rate derivatives:       
Financial institution counterparties:       
Loan/lease interest rate swaps – assets206,930
 747
 206,745
 2,649
Loan/lease interest rate swaps – liabilities735,583
 (14,623) 694,965
 (25,466)
Loan/lease interest rate caps – assets114,744
 547
 85,966
 575
Customer counterparties:       
Loan/lease interest rate swaps – assets735,583
 22,384
 694,965
 25,467
Loan/lease interest rate swaps – liabilities206,930
 (2,442) 206,745
 (2,649)
Loan/lease interest rate caps – liabilities114,744
 (547) 85,966
 (575)

The weighted-average rates paid and received for interest rate swaps outstanding at September 30, 2017March 31, 2019 were as follows:
 Weighted-Average
 
Interest
Rate
Paid
 
Interest
Rate
Received
Interest rate swaps:   
Fair value hedge loan/lease interest rate swaps2.35% 2.49%
Non-hedging interest rate swaps – financial institution counterparties4.18% 4.11%
Non-hedging interest rate swaps – customer counterparties4.11% 4.18%
 Weighted-Average
 
Interest
Rate
Paid
 
Interest
Rate
Received
Interest rate swaps:   
Fair value hedge loan/lease interest rate swaps2.32% 1.23%
Non-hedging interest rate swaps – financial institution counterparties3.96% 2.84%
Non-hedging interest rate swaps – customer counterparties2.84% 3.96%

The weighted-average strike rate for outstanding interest rate caps was 3.07%2.99% at September 30, 2017.March 31, 2019.
Commodity Derivatives. We enter into commodity swaps and option contracts that are not designated as hedging instruments primarily to accommodate the business needs of our customers. Upon the origination of a commodity swap or option contract with a customer, we simultaneously enter into an offsetting contract with a third party financial institution to mitigate the exposure to fluctuations in commodity prices.

The notional amounts and estimated fair values of non-hedging commodity swap and option derivative positions outstanding are presented in the following table. We obtain dealer quotations and use internal valuation models with observable market data inputs to value our commodity derivative positions.
   March 31, 2019 December 31, 2018
 
Notional
Units
 
Notional
Amount
 
Estimated
Fair Value
 
Notional
Amount
 
Estimated
Fair Value
Financial institution counterparties:         
Oil – assetsBarrels 1,520
 $5,495
 2,416
 $24,332
Oil – liabilitiesBarrels 1,546
 (6,882) 415
 (646)
Natural gas – assetsMMBTUs 4,061
 438
 5,745
 417
Natural gas – liabilitiesMMBTUs 10,630
 (910) 9,314
 (1,272)
Customer counterparties:         
Oil – assetsBarrels 1,650
 7,044
 415
 646
Oil – liabilitiesBarrels 1,416
 (5,377) 2,416
 (24,009)
Natural gas – assetsMMBTUs 10,660
 1,025
 10,236
 1,373
Natural gas – liabilitiesMMBTUs 4,031
 (433) 4,823
 (393)

   September 30, 2017 December 31, 2016
 
Notional
Units
 
Notional
Amount
 
Estimated
Fair Value
 
Notional
Amount
 
Estimated
Fair Value
Financial institution counterparties:         
Oil – assetsBarrels 977
 $1,530
 227
 $206
Oil – liabilitiesBarrels 1,082
 (1,311) 944
 (4,400)
Natural gas – assetsMMBTUs 3,351
 319
 
 
Natural gas – liabilitiesMMBTUs 1,546
 (81) 1,299
 (1,357)
Customer counterparties:         
Oil – assetsBarrels 1,096
 1,459
 944
 4,580
Oil – liabilitiesBarrels 963
 (1,327) 227
 (206)
Natural gas – assetsMMBTUs 1,546
 96
 1,299
 1,393
Natural gas – liabilitiesMMBTUs 3,351
 (285) 
 
Foreign Currency Derivatives. We enter into foreign currency forward contracts that are not designated as hedging instruments primarily to accommodate the business needs of our customers. Upon the origination of a foreign currency denominated transaction with a customer, we simultaneously enter into an offsetting contract with a third party financial institution to negate the exposure to fluctuations in foreign currency exchange rates. We also utilize foreign currency forward contracts that are not designated as hedging instruments to mitigate the economic effect of fluctuations in foreign currency exchange rates on foreign currency holdings and certain short-term, non-U.S. dollar denominated loans. The notional amounts and fair values of open foreign currency forward contracts were as follows:
   March 31, 2019 December 31, 2018
 
Notional
Currency
 
Notional
Amount
 
Estimated
Fair Value
 
Notional
Amount
 
Estimated
Fair Value
Financial institution counterparties:         
Forward contracts – assetsGBP 91
 $
 
 $
Forward contracts – liabilitiesCAD 7,451
 (48) 11,003
 (13)
Forward contracts – liabilitiesGBP 
 
 142
 (2)
Forward contracts – liabilitiesMXN 
 
 3,015
 (132)
Customer counterparties:         
Forward contracts – assetsCAD 7,434
 66
 10,979
 40
Forward contracts – assetsGBP 93
 1
 145
 4
Forward contracts – assetsMXN 
 
 3,000
 149

   September 30, 2017 December 31, 2016
 
Notional
Currency
 
Notional
Amount
 
Estimated
Fair Value
 
Notional
Amount
 
Estimated
Fair Value
Financial institution counterparties:         
Forward contracts – assetsEUR 135
 $1
 
 $
Forward contracts – assetsCAD 7,234
 15
 
 
Forward contracts – assetsGBP 547
 1
 
 
Forward contracts – assetsAUD 60
 1
 
 
Forward contracts – liabilitiesEUR 4,693
 (80) 870
 (9)
Forward contracts – liabilitiesCAD 
 
 2,214
 (21)
Forward contracts – liabilitiesGBP 1,075
 (24) 419
 (3)
Customer counterparties:         
Forward contracts – assetsEUR 3,867
 104
 
 
Forward contracts – assetsCAD 7,205
 15
 2,205
 29
Forward contracts – assetsGBP 192
 2
 
 

Gains, Losses and Derivative Cash Flows. For fair value hedges, the changes in the fair value of both the derivative hedging instrument and the hedged item are included in other non-interest income or other non-interest expense. The extent that such changes in fair value do not offset represents hedge ineffectiveness. Net cash flows from interest rate swaps on commercial loans/leases designated as hedging instruments in effective hedges of fair value are included in interest income on loans. For non-hedging derivative instruments, gains and losses due to changes in fair value and all cash flows are included in other non-interest income and other non-interest expense.
Amounts included in the consolidated statements of income related to interest rate derivatives designated as hedges of fair value were as follows:
 Three Months Ended 
 March 31,
 2019 2018
Commercial loan/lease interest rate swaps:   
Amount of gain (loss) included in interest income on loans$26
 $(42)
 Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
 2017 2016 2017 2016
Commercial loan/lease interest rate swaps:       
Amount of gain (loss) included in interest income on loans$(149) $(331) $(592) $(1,057)
Amount of (gain) loss included in other non-interest expense(2) 4
 (5) (3)

As stated above, we enter into non-hedge related derivative positions primarily to accommodate the business needs of our customers. Upon the origination of a derivative contract with a customer, we simultaneously enter into an offsetting derivative contract with a third party financial institution. We recognize immediate income based upon the difference in the bid/ask spread of the underlying transactions with our customers and the third party. Because we act only as an intermediary for our customer,

subsequent changes in the fair value of the underlying derivative contracts for the most part offset each other and do not significantly impact our results of operations.
Amounts included in the consolidated statements of income related to non-hedging interest rate, commodity and foreign currency derivative instruments are presented in the table below.
 Three Months Ended 
 March 31,
 2019 2018
Non-hedging interest rate derivatives:   
Other non-interest income$586
 $1,488
Other non-interest expense
 (21)
Non-hedging commodity derivatives:   
Other non-interest income103
 90
Non-hedging foreign currency derivatives:   
Other non-interest income17
 59

 Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
 2017 2016 2017 2016
Non-hedging interest rate derivatives:       
Other non-interest income$1,085
 $374
 $2,062
 $1,788
Other non-interest expense
 
 1
 
Non-hedging commodity derivatives:       
Other non-interest income231
 110
 387
 255
Non-hedging foreign currency derivatives:       
Other non-interest income83
 8
 101
 22
Counterparty Credit Risk. Our credit exposure relating to interest rate swaps, commodity swaps/options and foreign currency forward contracts with bank customers was approximately $23.6$29.4 million at September 30, 2017.March 31, 2019. This credit exposure is partly mitigated as transactions with customers are generally secured by the collateral, if any, securing the underlying transaction being hedged. Our credit exposure, net of collateral pledged, relating to interest rate swaps, commodity swaps/options and foreign currency forward contracts with upstream financial institution counterparties was approximately $10.3$12.1 million at September 30, 2017.March 31, 2019. This amount was primarily related to excess collateral we posted to counterparties. Collateral levels for upstream financial institution counterparties are monitored and adjusted as necessary. See Note 109 – Balance Sheet Offsetting and Repurchase Agreements for additional information regarding our credit exposure with upstream financial institution counterparties.
The aggregate fair value of securities we posted as collateral related to derivative contracts totaled $13.2 million$146 thousand at September 30, 2017.March 31, 2019. At such date, we also had $10.6$24.7 million in cash collateral on deposit with other financial institution counterparties.

Note 109 - Balance Sheet Offsetting and Repurchase Agreements
Balance Sheet Offsetting. Certain financial instruments, including resell and repurchase agreements and derivatives, may be eligible for offset in the consolidated balance sheet and/or subject to master netting arrangements or similar agreements. Our derivative transactions with upstream financial institution counterparties are generally executed under International Swaps and Derivative Association (“ISDA”) master agreements which include “right of set-off” provisions. In such cases there is generally a legally enforceable right to offset recognized amounts and there may be an intention to settle such amounts on a net basis. Nonetheless, we do not generally offset such financial instruments for financial reporting purposes.
Information about financial instruments that are eligible for offset in the consolidated balance sheet as of September 30, 2017March 31, 2019 is presented in the following tables.
 
Gross Amount
Recognized
 
Gross Amount
Offset
 
Net Amount
Recognized
March 31, 2019     
Financial assets:     
Derivatives:     
Loan/lease interest rate swaps and caps$2,172
 $
 $2,172
Commodity swaps and options5,933
 
 5,933
Foreign currency forward contracts
 
 
Total derivatives8,105
 
 8,105
Resell agreements9,642
 
 9,642
Total$17,747
 $
 $17,747
Financial liabilities:     
Derivatives:     
Loan/lease interest rate swaps$13,053
 $
 $13,053
Commodity swaps and options7,792
 
 7,792
Foreign currency forward contracts48
 
 48
Total derivatives20,893
 
 20,893
Repurchase agreements1,210,224
 
 1,210,224
Total$1,231,117
 $
 $1,231,117
 
Gross Amount
Recognized
 
Gross Amount
Offset
 
Net Amount
Recognized
September 30, 2017     
Financial assets:     
Derivatives:     
Loan/lease interest rate swaps and caps$1,590
 $
 $1,590
Commodity swaps and options1,849
 
 1,849
Foreign currency forward contracts18
 
 18
Total derivatives3,457
 
 3,457
Resell agreements17,642
 
 17,642
Total$21,099
 $
 $21,099
Financial liabilities:     
Derivatives:     
Loan/lease interest rate swaps$15,387
 $
 $15,387
Commodity swaps and options1,392
 
 1,392
Foreign currency forward contracts104
 
 104
Total derivatives16,883
 
 16,883
Repurchase agreements987,869
 
 987,869
Total$1,004,752
 $
 $1,004,752
   Gross Amounts Not Offset  
 
Net Amount
Recognized
 
Financial
Instruments
 Collateral 
Net
Amount
September 30, 2017       
Financial assets:       
Derivatives:       
Counterparty A$397
 $(397) $
 $
Counterparty B866
 (866) 
 
Counterparty C204
 (204) 
 
Counterparty D
 
 
 
Other counterparties1,990
 (1,631) (130) 229
Total derivatives3,457
 (3,098) (130) 229
Resell agreements17,642
 
 (17,642) 
Total$21,099
 $(3,098) $(17,772) $229
Financial liabilities:       
Derivatives:       
Counterparty A$8,984
 $(397) $(8,587) $
Counterparty B3,535
 (866) (2,669) 
Counterparty C1,128
 (204) (830) 94
Counterparty D
 
 
 
Other counterparties3,236
 (1,631) (1,605) 
Total derivatives16,883
 (3,098) (13,691) 94
Repurchase agreements987,869
 
 (987,869) 
Total$1,004,752
 $(3,098) $(1,001,560) $94


   Gross Amounts Not Offset  
 
Net Amount
Recognized
 
Financial
Instruments
 Collateral 
Net
Amount
March 31, 2019       
Financial assets:       
Derivatives:       
Counterparty A$320
 $(320) $
 $
Counterparty B3,022
 (3,022) 
 
Counterparty C34
 (34) 
 
Other counterparties4,729
 (3,969) (235) 525
Total derivatives8,105
 (7,345) (235) 525
Resell agreements9,642
 
 (9,642) 
Total$17,747
 $(7,345) $(9,877) $525
Financial liabilities:       
Derivatives:       
Counterparty A$4,753
 $(320) $(4,433) $
Counterparty B6,033
 (3,022) (3,011) 
Counterparty C183
 (34) (149) 
Other counterparties9,924
 (3,969) (5,670) 285
Total derivatives20,893
 (7,345) (13,263) 285
Repurchase agreements1,210,224
 
 (1,210,224) 
Total$1,231,117
 $(7,345) $(1,223,487) $285

Information about financial instruments that are eligible for offset in the consolidated balance sheet as of December 31, 20162018 is presented in the following tables.
 
Gross Amount
Recognized
 
Gross Amount
Offset
 
Net Amount
Recognized
December 31, 2018     
Financial assets:     
Derivatives:     
Loan/lease interest rate swaps and caps$3,100
 $
 $3,100
Commodity swaps and options24,749
 
 24,749
Foreign currency forward contracts
 
 
Total derivatives27,849
 
 27,849
Resell agreements11,642
 
 11,642
Total$39,491
 $
 $39,491
Financial liabilities:     
Derivatives:     
Loan/lease interest rate swaps$9,120
 $
 $9,120
Commodity swaps and options1,918
 
 1,918
Foreign currency forward contracts147
 
 147
Total derivatives11,185
 
 11,185
Repurchase agreements1,360,298
 
 1,360,298
Total$1,371,483
 $
 $1,371,483
 
Gross Amount
Recognized
 
Gross Amount
Offset
 
Net Amount
Recognized
December 31, 2016     
Financial assets:     
Derivatives:     
Loan/lease interest rate swaps and caps$3,592
 $
 $3,592
Commodity swaps and options206
 
 206
Foreign currency forward contracts
 
 
Total derivatives3,798
 
 3,798
Resell agreements9,642
 
 9,642
Total$13,440
 $
 $13,440
Financial liabilities:     
Derivatives:     
Loan/lease interest rate swaps$26,744
 $
 $26,744
Commodity swaps and options5,757
 
 5,757
Foreign currency forward contracts33
 
 33
Total derivatives32,534
 
 32,534
Repurchase agreements963,317
 
 963,317
Total$995,851
 $
 $995,851
   Gross Amounts Not Offset  
 
Net Amount
Recognized
 
Financial
Instruments
 Collateral 
Net
Amount
December 31, 2016       
Financial assets:       
Derivatives:       
Counterparty A$687
 $(687) $
 $
Counterparty B223
 (223) 
 
Counterparty C158
 (158) 
 
Counterparty D1,820
 (1,820) 
 
Other counterparties910
 (677) (64) 169
Total derivatives3,798
 (3,565) (64) 169
Resell agreements9,642
 
 (9,642) 
Total$13,440
 $(3,565) $(9,706) $169
Financial liabilities:       
Derivatives:       
Counterparty A$11,233
 $(687) $(10,026) $520
Counterparty B6,867
 (223) (6,344) 300
Counterparty C4,578
 (158) (4,415) 5
Counterparty D7,706
 (1,820) (5,886) 
Other counterparties2,150
 (677) (676) 797
Total derivatives32,534
 (3,565) (27,347) 1,622
Repurchase agreements963,317
 
 (963,317) 
Total$995,851
 $(3,565) $(990,664) $1,622


   Gross Amounts Not Offset  
 
Net Amount
Recognized
 
Financial
Instruments
 Collateral 
Net
Amount
December 31, 2018       
Financial assets:       
Derivatives:       
Counterparty A$598
 $(598) $
 $
Counterparty B7,255
 (3,380) (3,875) 
Counterparty C81
 (81) 
 
Other counterparties19,915
 (2,084) (17,776) 55
Total derivatives27,849
 (6,143) (21,651) 55
Resell agreements11,642
 
 (11,642) 
Total$39,491
 $(6,143) $(33,293) $55
Financial liabilities:       
Derivatives:       
Counterparty A$4,293
 $(598) $(3,651) $44
Counterparty B3,380
 (3,380) 
 
Counterparty C326
 (81) (245) 
Other counterparties3,186
 (2,084) (725) 377
Total derivatives11,185
 (6,143) (4,621) 421
Repurchase agreements1,360,298
 
 (1,360,298) 
Total$1,371,483
 $(6,143) $(1,364,919) $421

Repurchase Agreements. We utilize securities sold under agreements to repurchase to facilitate the needs of our customers and to facilitate secured short-term funding needs. Securities sold under agreements to repurchase are stated at the amount of cash received in connection with the transaction. We monitor collateral levels on a continuous basis. We may be required to provide additional collateral based on the fair value of the underlying securities. Securities pledged as collateral under repurchase agreements are maintained with our safekeeping agents.
The remaining contractual maturity of repurchase agreements in the consolidated balance sheets as of September 30, 2017March 31, 2019 and December 31, 20162018 is presented in the following tables.
 Remaining Contractual Maturity of the Agreements
 Overnight and Continuous Up to 30 Days 30-90 Days Greater than 90 Days Total
March 31, 2019         
Repurchase agreements:         
U.S. Treasury$1,098,844
 $
 $
 $
 $1,098,844
Residential mortgage-backed securities111,380
 
 
 
 111,380
Total borrowings$1,210,224
 $
 $
 $
 $1,210,224
Gross amount of recognized liabilities for repurchase agreements $1,210,224
Amounts related to agreements not included in offsetting disclosures above $
          
December 31, 2018         
Repurchase agreements:         
U.S. Treasury$1,334,063
 $
 $
 $
 $1,334,063
Residential mortgage-backed securities26,235
 
 
 
 26,235
Total borrowings$1,360,298
 $
 $
 $
 $1,360,298
Gross amount of recognized liabilities for repurchase agreements $1,360,298
Amounts related to agreements not included in offsetting disclosures above $

 Remaining Contractual Maturity of the Agreements
 Overnight and Continuous Up to 30 Days 30-90 Days Greater than 90 Days Total
September 30, 2017         
Repurchase agreements:         
U.S. Treasury$907,509
 $
 $
 $
 $907,509
Residential mortgage-backed securities80,360
 
 
 
 80,360
Total borrowings$987,869
 $
 $
 $
 $987,869
Gross amount of recognized liabilities for repurchase agreements $987,869
Amounts related to agreements not included in offsetting disclosures above $
          
December 31, 2016         
Repurchase agreements:         
U.S. Treasury$841,475
 $
 $
 $
 $841,475
Residential mortgage-backed securities121,842
 
 
 
 121,842
Total borrowings$963,317
 $
 $
 $
 $963,317
Gross amount of recognized liabilities for repurchase agreements $963,317
Amounts related to agreements not included in offsetting disclosures above $

Note 1110 - Stock-Based Compensation
A combined summary of activity in our active stock plans is presented in the table. Performance stock units outstanding are presented assuming attainment of the maximum payout rate as set forth by the performance criteria. The target award level for performance stock units granted in 2016 was 29,240.As of September 30, 2017,March 31, 2019, there were 1,499,3991,268,144 shares remaining available for grant for future stock-based compensation awards.
  
Director Deferred
Stock Units
Outstanding
 
Non-Vested Stock
Awards/Stock Units
Outstanding
 Performance Stock Units Outstanding 
Stock Options
Outstanding
  Number of Units 
Weighted-
Average
Fair Value
at Grant
 
Number
of Shares/Units
 
Weighted-
Average
Fair Value
at Grant
 Number of Units 
Weighted-
Average
Fair Value
at Grant
 
Number
of Shares
 
Weighted-
Average
Exercise
Price
Balance, January 1, 2019 48,910
 $71.14
 383,797
 $85.59
 125,809
 $82.55
 2,352,008
 $63.55
Authorized 
 
 
 
 
 
 
 
Granted 
 
 1,631
 91.95
 
 
 
 
Exercised/vested 
 
 (17,800) 65.11
 
 
 (83,065) 58.82
Forfeited/expired 
 
 (998) 92.65
 
 
 (4,500) 65.11
Balance, March 31, 2019 48,910
 $71.14
 366,630
 $86.59
 125,809
 $82.55
 2,264,443
 $63.72
  
Director Deferred
Stock Units
Outstanding
 
Non-Vested Stock
Awards/Stock Units
Outstanding
 Performance Stock Units Outstanding 
Stock Options
Outstanding
  Number of Units 
Weighted-
Average
Fair Value
at Grant
 
Number
of Shares/Units
 
Weighted-
Average
Fair Value
at Grant
 Number of Units 
Weighted-
Average
Fair Value
at Grant
 
Number
of Shares
 
Weighted-
Average
Exercise
Price
Balance, January 1, 2017 53,659
 $61.48
 256,850
 $73.43
 43,860
 $69.70
 4,089,028
 $62.67
Authorized 
 
 
 
 
 
 
 
Granted 5,447
 95.37
 
 
 
 
 
 
Exercised/vested (6,098) 62.29
 (1,730) 76.07
 
 
 (766,971) 59.22
Forfeited/expired 
 
 (2,860) 76.07
 
 
 (50,764) 69.65
Balance, September 30, 2017 53,008
 $64.87
 252,260
 $73.38
 43,860
 $69.70
 3,271,293
 $63.37


Shares issued in connection with stock compensation awards are issued from available treasury shares. If no treasury shares are available, new shares are issued from available authorized shares. Shares issued in connection with stock compensation awards along with other related information were as follows:
 Three Months Ended 
 March 31,
 2019 2018
New shares issued from available authorized shares
 
Issued from available treasury stock100,865
 318,110
Total100,865
 318,110
    
Proceeds from stock option exercises$4,885
 $19,165
 Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
 2017 2016 2017 2016
New shares issued from available authorized shares9,299
 
 602,662
 
Issued from available treasury stock13,425
 841,846
 172,137
 908,921
Total22,724
 841,846
 774,799
 908,921
        
Proceeds from stock option exercises$1,274
 $44,287
 $45,422
 $47,873

Stock-based compensation expense is recognized ratably over the requisite service period for all awards. For most stock option awards, the service period generally matches the vesting period. For stock options granted to certain executive officers and for non-vested stock units granted to all participants, the service period does not extend past the date the participant reaches 65 years of age. Deferred stock units granted to non-employee directors generally have immediate vesting and the related expense is fully recognized on the date of grant. For performance stock units, the service period generally matches the three-year performance period specified by the award, however, the service period does not extend past the date the participant reaches 65 years of age. Expense recognized each period is dependent upon our estimate of the number of shares that will ultimately be issued.
Stock-based compensation expense and the related income tax benefit is presented in the following table.
 Three Months Ended 
 March 31,
 2019 2018
Stock options$382
 $1,085
Non-vested stock awards/stock units2,135
 1,468
Director deferred stock units
 
Performance stock units1,137
 622
Total$3,654
 $3,175
Income tax benefit$584
 $667
 Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
 2017 2016 2017 2016
Stock options$1,532
 $2,163
 $4,892
 $6,405
Non-vested stock awards/stock units813
 358
 2,747
 1,073
Director deferred stock units
 
 519
 520
Performance stock units377
 
 855
 
Total$2,722
 $2,521
 $9,013
 $7,998
Income tax benefit$953
 $882
 $3,155
 $2,799

Unrecognized stock-based compensation expense at September 30, 2017March 31, 2019 is presented in the table below. Unrecognized stock-based compensation expense related to performance stock units is presented assuming attainment of the maximum payout rate as set forth by the performance criteria.
Stock options$866
Non-vested stock awards/stock units15,724
Performance stock units5,390
Total$21,980
Stock options$6,952
Non-vested stock awards/stock units7,448
Performance stock units2,202
Total$16,602


Note 1211 - Earnings Per Common Share
Earnings per common share is computed using the two-class method as more fully described in our 20162018 Form 10-K. The following table presents a reconciliation of net income available to common shareholders, net earnings allocated to common stock and the number of shares used in the calculation of basic and diluted earnings per common share.
 Three Months Ended 
 March 31,
 2019 2018
Net income$116,496
 $106,480
Less: Preferred stock dividends2,016
 2,016
Net income available to common shareholders114,480
 104,464
Less: Earnings allocated to participating securities980
 702
Net earnings allocated to common stock$113,500
 $103,762
    
Distributed earnings allocated to common stock$42,238
 $36,306
Undistributed earnings allocated to common stock71,262
 67,456
Net earnings allocated to common stock$113,500
 $103,762
    
Weighted-average shares outstanding for basic earnings per common share63,009,060
 63,649,198
Dilutive effect of stock compensation818,896
 1,012,997
Weighted-average shares outstanding for diluted earnings per common share63,827,956
 64,662,195
 Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
 2017 2016 2017 2016
Net income$93,131
 $80,219
 $263,625
 $220,542
Less: Preferred stock dividends2,016
 2,016
 6,047
 6,047
Net income available to common shareholders91,115
 78,203
 257,578
 214,495
Less: Earnings allocated to participating securities475
 282
 1,346
 769
Net earnings allocated to common stock$90,640
 $77,921
 $256,232
 $213,726
        
Distributed earnings allocated to common stock$36,174
 $33,918
 $107,194
 $100,203
Undistributed earnings allocated to common stock54,466
 44,003
 149,038
 113,523
Net earnings allocated to common stock$90,640
 $77,921
 $256,232
 $213,726
        
Weighted-average shares outstanding for basic earnings per common share63,667,356
 62,449,660
 63,822,011
 62,114,075
Dilutive effect of stock compensation897,945
 691,543
 957,337
 448,290
Weighted-average shares outstanding for diluted earnings per common share64,565,301
 63,141,203
 64,779,348
 62,562,365

Note 1312 - Defined Benefit Plans
The components of the combined net periodic expense (benefit) for our defined benefit pension plans are presented in the table below.
 Three Months Ended 
 March 31,
 2019 2018
Expected return on plan assets, net of expenses$(2,693) $(2,979)
Interest cost on projected benefit obligation1,618
 1,475
Net amortization and deferral1,406
 1,250
Net periodic expense (benefit)$331
 $(254)
 Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
 2017 2016 2017 2016
Expected return on plan assets, net of expenses$(2,779) $(2,890) $(8,338) $(8,669)
Interest cost on projected benefit obligation1,547
 1,732
 4,642
 5,230
Net amortization and deferral1,357
 1,585
 4,072
 4,691
SERP settlement costs
 
 
 187
Net periodic expense (benefit)$125
 $427
 $376
 $1,439

Our non-qualified defined benefit pension plan is not funded. No contributions to the qualified defined benefit pension plan were made during the ninethree months ended September 30, 2017.March 31, 2019. We do not expect to make any contributions to the qualified defined benefit plan during the remainder of 2017.2019.

Note 1413 - Income Taxes
Income tax expense was as follows:
 Three Months Ended 
 March 31,
 2019 2018
Current income tax expense (benefit)$14,999
 $746
Deferred income tax expense (benefit)(1,044) 10,411
Income tax expense, as reported$13,955
 $11,157
    
Effective tax rate10.7% 9.5%

 Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
 2017 2016 2017 2016
Current income tax expense$15,224
 $12,848
 $44,636
 $40,251
Deferred income tax expense (benefit)(5,332) (1,996) (9,505) (11,629)
Income tax expense, as reported$9,892
 $10,852
 $35,131
 $28,622
        
Effective tax rate9.6% 11.9% 11.8% 11.5%
NetWe had a net deferred tax assets totaled $28.9liability totaling $21.0 million at September 30, 2017March 31, 2019 and $63.7a net deferred tax asset totaling $19.8 million at December 31, 2016.2018. The change in net deferred taxes was primarily related to unrealized gains on available-for-sale securities during the three months ended March 31, 2019. No valuation allowance for deferred tax assets was recorded at September 30, 2017March 31, 2019 as management believes it is more likely than not that all of the deferred tax assets will be realized because they were supported by recoverable taxes paid in prior years.against deferred tax liabilities and projected future taxable income.

The effective income tax rates differed from the U.S. statutory ratefederal income tax rates of 35%21% during the comparable periods primarily due to the effect of tax-exempt income from loans, securities and life insurance policies and the income tax effects associated with stock-based compensation. The effective income tax rates for the three and nine months ended September 30, 2017 were also impacted by the correction of an over-accrual of taxes that resulted from incorrectly classifying certain tax-exempt loans as taxable for federal income tax purposes since 2013. As a result, we recognized tax benefits totaling $3.7 million, which included $2.9 million related to the 2013 through 2016 tax years and $756 thousand related to the first and second quarters of 2017. There were no unrecognized tax benefits during any of the reported periods. Interest and/or penalties related to income taxes are reported as a component of income tax expense. Such amounts were not significant during the reported periods.
We file income tax returns in the U.S. federal jurisdiction. We are no longer subject to U.S. federal income tax examinations by tax authorities for years before 2013.2015.

Note 1514 - Other Comprehensive Income (Loss)
The before and after tax amounts allocated to each component of other comprehensive income (loss) are presented in the following table. Reclassification adjustments related to securities available for sale are included in net gain (loss) on securities transactions in the accompanying consolidated statements of income. Reclassification adjustments related to defined-benefit post-retirement benefit plans are included in the computation of net periodic pension expense (see Note 1312 – Defined Benefit Plans).
 Three Months Ended 
 March 31, 2019
 Three Months Ended 
 March 31, 2018
 
Before Tax
Amount
 
Tax  Expense,
(Benefit)
 
Net of  Tax
Amount
 
Before Tax
Amount
 
Tax  Expense,
(Benefit)
 
Net of  Tax
Amount
Securities available for sale and transferred securities:           
Change in net unrealized gain/loss during the period$198,146
 $41,611
 $156,535
 $(178,904) $(37,570) $(141,334)
Change in net unrealized gain on securities transferred to held to maturity(344) (72) (272) (2,619) (550) (2,069)
Reclassification adjustment for net (gains) losses included in net income
 
 
 19
 4
 15
Total securities available for sale and transferred securities197,802
 41,539
 156,263
 (181,504) (38,116) (143,388)
Defined-benefit post-retirement benefit plans:           
Change in the net actuarial gain/loss
 
 
 
 
 
Reclassification adjustment for net amortization of actuarial gain/loss included in net income as a component of net periodic cost (benefit)1,406
 295
 1,111
 1,250
 263
 987
Total defined-benefit post-retirement benefit plans1,406
 295
 1,111
 1,250
 263
 987
Total other comprehensive income (loss)$199,208
 $41,834
 $157,374
 $(180,254) $(37,853) $(142,401)
 Three Months Ended 
 September 30, 2017
 Three Months Ended 
 September 30, 2016
 
Before Tax
Amount
 
Tax  Expense,
(Benefit)
 
Net of  Tax
Amount
 
Before Tax
Amount
 
Tax  Expense,
(Benefit)
 
Net of  Tax
Amount
Securities available for sale and transferred securities:           
Change in net unrealized gain/loss during the period$7,082
 $2,479
 $4,603
 $(95,641) $(33,473) $(62,168)
Change in net unrealized gain on securities transferred to held to maturity(3,514) (1,230) (2,284) (7,278) (2,547) (4,731)
Reclassification adjustment for net (gains) losses included in net income4,867
 1,703
 3,164
 37
 12
 25
Total securities available for sale and transferred securities8,435
 2,952
 5,483
 (102,882) (36,008) (66,874)
Defined-benefit post-retirement benefit plans:           
Change in the net actuarial gain/loss
 
 
 
 
 
Reclassification adjustment for net amortization of actuarial gain/loss included in net income as a component of net periodic cost (benefit)1,357
 475
 882
 1,585
 555
 1,030
Total defined-benefit post-retirement benefit plans1,357
 475
 882
 1,585
 555
 1,030
Total other comprehensive income (loss)$9,792
 $3,427
 $6,365
 $(101,297) $(35,453) $(65,844)
 
 Nine Months Ended 
 September 30, 2017
 Nine Months Ended 
 September 30, 2016
 
Before Tax
Amount
 
Tax  Expense,
(Benefit)
 
Net of  Tax
Amount
 
Before Tax
Amount
 
Tax  Expense,
(Benefit)
 
Net of  Tax
Amount
Securities available for sale and transferred securities:           
Change in net unrealized gain/loss during the period$131,283
 $45,949
 $85,334
 $191,865
 $67,154
 $124,711
Change in net unrealized gain on securities transferred to held to maturity(13,660) (4,781) (8,879) (24,629) (8,620) (16,009)
Reclassification adjustment for net (gains) losses included in net income4,917
 1,721
 3,196
 (14,866) (5,204) (9,662)
Total securities available for sale and transferred securities122,540
 42,889
 79,651
 152,370
 53,330
 99,040
Defined-benefit post-retirement benefit plans:           
Change in the net actuarial gain/loss
 
 
 (862) (302) (560)
Reclassification adjustment for net amortization of actuarial gain/loss included in net income as a component of net periodic cost (benefit)4,072
 1,425
 2,647
 4,878
 1,708
 3,170
Total defined-benefit post-retirement benefit plans4,072
 1,425
 2,647
 4,016
 1,406
 2,610
Total other comprehensive income (loss)$126,612
 $44,314
 $82,298
 $156,386
 $54,736
 $101,650


Activity in accumulated other comprehensive income (loss), net of tax, was as follows:
 
Securities
Available
For Sale
 
Defined
Benefit
Plans
 
Accumulated
Other
Comprehensive
Income
Balance January 1, 2019$(16,103) $(47,497) $(63,600)
Other comprehensive income (loss) before reclassifications156,263
 
 156,263
Reclassification of amounts included in net income
 1,111
 1,111
Net other comprehensive income (loss) during period156,263
 1,111
 157,374
Balance at March 31, 2019$140,160
 $(46,386) $93,774
      
Balance January 1, 2018$117,230
 $(37,718) $79,512
Other comprehensive income (loss) before reclassifications(143,403) 
 (143,403)
Reclassification of amounts included in net income15
 987
 1,002
Net other comprehensive income (loss) during period(143,388) 987
 (142,401)
Reclassification of certain income tax effects related to the change in the U.S. statutory federal income tax rate under the Tax Cuts and Jobs Act to retained earnings17,557
 (8,022) 9,535
Balance at March 31, 2018$(8,601) $(44,753) $(53,354)

 
Securities
Available
For Sale
 
Defined
Benefit
Plans
 
Accumulated
Other
Comprehensive
Income
Balance January 1, 2017$16,153
 $(40,776) $(24,623)
Other comprehensive income (loss) before reclassifications76,455
 
 76,455
Amounts reclassified from accumulated other comprehensive income (loss)3,196
 2,647
 5,843
Net other comprehensive income (loss) during period79,651
 2,647
 82,298
Balance at September 30, 2017$95,804
 $(38,129) $57,675
      
Balance January 1, 2016$160,611
 $(46,748) $113,863
Other comprehensive income (loss) before reclassifications108,702
 2,489
 111,191
Amounts reclassified from accumulated other comprehensive income (loss)(9,662) 121
 (9,541)
Net other comprehensive income (loss) during period99,040
 2,610
 101,650
Balance at September 30, 2016$259,651
 $(44,138) $215,513

Note 1615 – Operating Segments
We are managed under a matrix organizational structure whereby our two primary operating segments, Banking and Frost Wealth Advisors, overlap a regional reporting structure. See our 20162018 Form 10-K for additional information regarding our operating segments. Summarized operating results by segment were as follows:
 Banking 
Frost  Wealth
Advisors
 Non-Banks Consolidated
Revenues from (expenses to) external customers:       
Three months ended:       
March 31, 2019$308,613
 $37,351
 $(2,710) $343,254
March 31, 2018288,561
 35,081
 (2,449) 321,193
Net income (loss):       
Three months ended:       
March 31, 2019$112,917
 $6,400
 $(2,821) $116,496
March 31, 2018103,641
 5,634
 (2,795) 106,480

 Banking 
Frost  Wealth
Advisors
 Non-Banks Consolidated
Revenues from (expenses to) external customers:       
Three months ended:       
September 30, 2017$266,582
 $36,529
 $(2,285) $300,826
September 30, 2016244,343
 33,536
 (1,258) 276,621
Nine months ended:       
September 30, 2017$786,743
 $107,829
 $(5,669) $888,903
September 30, 2016737,060
 97,484
 (3,537) 831,007
Net income (loss):       
Three months ended:       
September 30, 2017$88,368
 $6,417
 $(1,654) $93,131
September 30, 201676,347
 4,797
 (925) 80,219
Nine months ended:       
September 30, 2017$250,766
 $17,990
 $(5,131) $263,625
September 30, 2016210,454
 13,809
 (3,721) 220,542

Note 1716 – Fair Value Measurements
The fair value of an asset or liability is the price that would be received to sell that asset or paid to transfer that liability in an orderly transaction occurring in the principal market (or most advantageous market in the absence of a principal market) for such asset or liability. In estimating fair value, we utilize valuation techniques that are consistent with the market approach, the income approach and/or the cost approach. Such valuation techniques are consistently applied. Inputs to valuation techniques include the assumptions that market participants would use in pricing an asset or liability. ASC Topic 820 establishes a three-level fair value hierarchy for valuation inputs that gives the highest priority to quoted prices in active markets for identical assets or liabilities and the lowest priority to unobservable inputs. See our 20162018 Form 10-K for additional information regarding the fair value hierarchy and a description of our valuation techniques.
Financial Assets and Financial Liabilities. The table below summarizes financial assets and financial liabilities measured at fair value on a recurring basis as of September 30, 2017March 31, 2019 and December 31, 2016,2018, segregated by the level of the valuation inputs within the fair value hierarchy of ASC Topic 820 utilized to measure fair value.
Level 1
Inputs
 Level 2
Inputs
 Level 3
Inputs
 Total Fair
Value
Level 1
Inputs
 Level 2
Inputs
 Level 3
Inputs
 Total Fair
Value
September 30, 2017       
March 31, 2019       
Securities available for sale:              
U.S. Treasury$3,473,628
 $
 $
 $3,473,628
$3,445,068
 $
 $
 $3,445,068
Residential mortgage-backed securities
 681,195
 
 681,195

 1,227,435
 
 1,227,435
States and political subdivisions
 5,987,739
 
 5,987,739

 7,298,726
 
 7,298,726
Other
 42,538
 
 42,538

 42,734
 
 42,734
Trading account securities:              
U.S. Treasury18,814
 
 
 18,814
22,503
 
 
 22,503
States and political subdivisions
 907
 
 907

 2,728
 
 2,728
Derivative assets:              
Interest rate swaps, caps and floors
 23,974
 
 23,974

 26,990
 
 26,990
Commodity swaps and options
 3,404
 
 3,404

 14,002
 
 14,002
Foreign currency forward contracts139
 
 
 139
67
 
 
 67
Derivative liabilities:              
Interest rate swaps, caps and floors
 18,376
 
 18,376

 17,244
 
 17,244
Commodity swaps and options
 3,004
 
 3,004

 13,602
 
 13,602
Foreign currency forward contracts104
 
 
 104
48
 
 
 48
December 31, 2016       
Securities available for sale:       
U.S. Treasury$4,019,731
 $
 $
 $4,019,731
Residential mortgage-backed securities
 785,167
 
 785,167
States and political subdivisions
 5,355,885
 
 5,355,885
Other
 42,494
 
 42,494
Trading account securities:       
U.S. Treasury16,594
 
 
 16,594
States and political subdivisions
 109
 
 109
Derivative assets:       
Interest rate swaps, caps and floors
 29,059
 
 29,059
Commodity swaps and options
 6,179
 
 6,179
Foreign currency forward contracts29
 
 
 29
Derivative liabilities:       
Interest rate swaps, caps and floors
 29,968
 
 29,968
Commodity swaps and options
 5,963
 
 5,963
Foreign currency forward contracts33
 
 
 33

 Level 1
Inputs
 Level 2
Inputs
 Level 3
Inputs
 Total Fair
Value
December 31, 2018       
Securities available for sale:       
U.S. Treasury$3,427,689
 $
 $
 $3,427,689
Residential mortgage-backed securities
 829,740
 
 829,740
States and political subdivisions
 7,087,202
 
 7,087,202
Other
 42,690
 
 42,690
Trading account securities:       
U.S. Treasury21,928
 
 
 21,928
States and political subdivisions
 2,158
 
 2,158
Derivative assets:       
Interest rate swaps, caps and floors
 19,806
 
 19,806
Commodity swaps and options
 26,768
 
 26,768
Foreign currency forward contracts193
 
 
 193
Derivative liabilities:       
Interest rate swaps, caps and floors
 18,520
 
 18,520
Commodity swaps and options
 26,320
 
 26,320
Foreign currency forward contracts147
 
 
 147

Certain financial assets and financial liabilities are measured at fair value on a nonrecurring basis; that is, the instruments are not measured at fair value on an ongoing basis but are subject to fair value adjustments in certain circumstances (for example, when there is evidence of impairment). Financial assets measured at fair value on a non-recurring basis during the reported periods include certain impaired loans reported at the fair value of the underlying collateral if repayment is expected solely from the collateral. The following table presents impaired loans that were remeasured and reported at fair value through a specific valuation allowance allocation of the allowance for loan losses based upon the fair value of the underlying collateral during the reported periods.
 Three Months Ended 
 March 31, 2019
 Three Months Ended 
 March 31, 2018
 Level 2 Level 3 Level 2 Level 3
Carrying value of impaired loans before allocations$11,487
 $37,525
 $365
 $56,788
Specific valuation allowance (allocations) reversals of prior allocations(256) (3,441) (64) (1,520)
Fair value$11,231
 $34,084
 $301
 $55,268

 Nine Months Ended 
 September 30, 2017
 Nine Months Ended 
 September 30, 2016
 Level 2 Level 3 Level 2 Level 3
Carrying value of impaired loans before allocations$
 $64,287
 $
 $11,023
Specific valuation allowance (allocations) reversals of prior allocations
 (13,477) 
 (3,750)
Fair value$
 $50,810
 $
 $7,273
Non-Financial Assets and Non-Financial Liabilities. We do not have any non-financial assets or non-financial liabilities measured at fair value on a recurring basis. Non-financial assets measured at fair value on a non-recurring basis during the reported periods include certain foreclosed assets which, upon initial recognition, were remeasured and reported at fair value through a charge-off to the allowance for loan losses and certain foreclosed assets which, subsequent to their initial recognition, were remeasured at fair value through a write-down included in other non-interest expense. The following table presents foreclosed assets that were remeasured and reported at fair value during the reported periods:
 Three Months Ended 
 March 31,
 2019 2018
Foreclosed assets remeasured at initial recognition:   
Carrying value of foreclosed assets prior to remeasurement$
 $7
Charge-offs recognized in the allowance for loan losses
 
Fair value$
 $7
Foreclosed assets remeasured subsequent to initial recognition:   
Carrying value of foreclosed assets prior to remeasurement$
 $1,823
Write-downs included in other non-interest expense
 (473)
Fair value$
 $1,350

 Nine Months Ended 
 September 30, 2017
 2017 2016
Foreclosed assets remeasured at initial recognition:   
Carrying value of foreclosed assets prior to remeasurement$
 $425
Charge-offs recognized in the allowance for loan losses
 (3)
Fair value$
 $422
Foreclosed assets remeasured subsequent to initial recognition:   
Carrying value of foreclosed assets prior to remeasurement$89
 $492
Write-downs included in other non-interest expense(16) (217)
Fair value$73
 $275

Financial Instruments Reported at Amortized Cost. The estimated fair values of financial instruments that are reported at amortized cost in our consolidated balance sheets, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value, were as follows:
 March 31, 2019 December 31, 2018
 
Carrying
Amount
 
Estimated
Fair Value
 
Carrying
Amount
 
Estimated
Fair Value
Financial assets:       
Level 2 inputs:       
Cash and cash equivalents$2,281,454
 $2,281,454
 $3,955,779
 $3,955,779
Securities held to maturity1,077,279
 1,097,858
 1,106,057
 1,116,953
Cash surrender value of life insurance policies184,371
 184,371
 183,473
 183,473
Accrued interest receivable142,977
 142,977
 188,989
 188,989
Level 3 inputs:       
Loans, net14,269,989
 14,256,028
 13,967,601
 13,933,239
Financial liabilities:       
Level 2 inputs:       
Deposits26,294,863
 26,291,609
 27,149,204
 27,143,572
Federal funds purchased and repurchase agreements1,227,149
 1,227,149
 1,367,548
 1,367,548
Junior subordinated deferrable interest debentures136,256
 137,115
 136,242
 137,115
Subordinated notes payable and other borrowings98,747
 101,238
 98,708
 98,458
Accrued interest payable7,844
 7,844
 7,394
 7,394

 September 30, 2017 December 31, 2016
 
Carrying
Amount
 
Estimated
Fair Value
 
Carrying
Amount
 
Estimated
Fair Value
Financial assets:       
Level 2 inputs:       
Cash and cash equivalents$5,091,903
 $5,091,903
 $4,141,445
 $4,141,445
Securities held to maturity1,442,222
 1,476,653
 2,250,460
 2,262,747
Cash surrender value of life insurance policies179,789
 179,789
 177,884
 177,884
Accrued interest receivable118,035
 118,035
 156,714
 156,714
Level 3 inputs:       
Loans, net12,552,001
 12,574,862
 11,822,347
 11,903,956
Financial liabilities:       
Level 2 inputs:       
Deposits26,403,269
 26,398,885
 25,811,575
 25,812,039
Federal funds purchased and repurchase agreements997,919
 997,919
 976,992
 976,992
Junior subordinated deferrable interest debentures136,170
 137,115
 136,127
 137,115
Subordinated notes payable and other borrowings98,512
 102,072
 99,990
 100,000
Accrued interest payable1,737
 1,737
 1,204
 1,204
Under ASC Topic 825, entities may choose to measure eligible financial instruments at fair value at specified election dates. The fair value measurement option (i) may be applied instrument by instrument, with certain exceptions, (ii) is generally irrevocable and (iii) is applied only to entire instruments and not to portions of instruments. Unrealized gains and losses on items for which the fair value measurement option has been elected must be reported in earnings at each subsequent reporting date. During the reported periods, we had no financial instruments measured at fair value under the fair value measurement option.

Note 1817 - Accounting Standards Updates
Information about certain recently issued accounting standards updates is presented below. Also refer to Note 2120 - Accounting Standards Updates in our 20162018 Form 10-K for additional information related to previously issued accounting standards updates.
Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers (Topic 606).” ASU 2014-09 implements a common revenue standard that clarifies the principles for recognizing revenue. The core principle of ASU 2014-09 is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve that core principle, an entity should apply the following steps: (i) identify the contract(s) with a customer, (ii) identify the performance obligations in the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations in the contract and (v) recognize revenue when (or as) the entity satisfies a performance obligation. ASU 2014-09 was originally going to be effective for us on January 1, 2017; however, the FASB issued ASU 2015-14, “Revenue from Contracts with Customers (Topic 606) – Deferral of the Effective Date" which deferred the effective date of ASU 2014-09 by one year to January 1, 2018. Our revenue is comprised of net interest income on financial assets and financial liabilities, which is explicitly excluded from the scope of ASU 2014-09, and non-interest income. We expect that ASU 2014-09 will require us to change how we recognize certain recurring revenue streams within trust and investment management fees, insurance commissions and fees and other categories of non-interest income; however, we do not expect these changes to have a significant impact on our financial statements. We expect to adopt the standard in the first quarter of 2018 with a cumulative effect adjustment to opening retained earnings, if such adjustment is deemed to be significant.
ASU 2016-02,“Leases “Leases (Topic 842).” ASU 2016-02, will, among other things, requirerequires lessees to recognize a lease liability, which is a lessee's obligation to make lease payments arising from a lease, measured on a discounted basis; and a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. We adopted ASU 2016-02, does not significantly changealong with several other subsequent codification updates related to lease accounting, requirements applicable to lessors; however, certain changes were made to align, where necessary, lessor accounting with the lessee accounting model and ASC Topic 606, “Revenue from Contracts with Customers.” ASU 2016-02 will be effective for us onas of January 1, 2019 and will require transition using a modified retrospective approach2019. See Note 1 - Significant Accounting Policies for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. We are currently evaluating the potential impact of ASU 2016-02 on our financial statements. In that regard, we have selected, and will soon implement, a third-party vendor solution to assist us in the application of ASU 2016-02.additional information.
ASU 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 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 and requires enhanced disclosures related to the significant estimates and judgments used in estimating credit losses, as well as the credit quality and underwriting standards of an organization’s portfolio. In addition, ASU 2016-13 amends the accounting for credit losses on available-for-sale debt securities and purchased financial assets with credit deterioration. ASU 2016-13 will be effective on January 1, 2020. We are currently evaluating the potential impact of ASU 2016-13 on our financial statements. In that regard, we have formed a cross-functional working group, under the direction of our Chief Financial Officer and our Chief RiskCredit Officer. The working group is comprised of individuals from various functional areas including credit, risk management, finance and information technology, among others. We are currently developing anworking through our implementation plan to includewhich includes assessment and documentation of processes, portfolio segmentation,internal controls and data sources; model development, documentation and validation; and system requirements and the identification of data and resource needs,configuration, among other things. We are also currently evaluating selectedin the process of implementing a third-party vendor solutionssolution to assist us in the application of the ASU 2016-13. The adoption of the ASU 2016-13 is likely tocould result in an increase in the allowance for loan losses as a result of changing from an “incurred loss” model, which encompasses allowances for current known and inherent losses within the portfolio, to an “expected loss” model, which encompasses allowances for losses expected to be incurred over the life of the portfolio. Furthermore, ASU 2016-13 will necessitate that we establish an allowance for expected credit losses onfor certain debt securities.securities and other financial assets. While we are currently unable to reasonably estimate the impact of adopting ASU 2016-13, we expect that the impact of adoption will be significantly influenced by the composition, characteristics and quality of our loan and securities portfolios as well as the prevailing economic conditions and forecasts as of the adoption date.
ASU 2017-04, “Intangibles - Goodwill and Other (Topic 350) - Simplifying the Test for Goodwill Impairment.” ASU 2017-04 eliminates Step 2 from the goodwill impairment test which required entities to compute the implied fair value of goodwill. Under ASU 2017-04, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. ASU 2017-04 will be effective for us on January 1, 2020, with early adoption permitted for interim or annual impairment tests beginning in 2017. ASU 2017-04 is not expected to have a significant impact on our financial statements.

ASU 2017-05, “Other Income - Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20) - Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets.” ASU 2017-05 clarifies the scope of Subtopic 610-20 and adds guidance for partial sales of nonfinancial assets, including partial sales of real estate. Historically, U.S. GAAP contained several different accounting models to evaluate whether the transfer of certain assets qualified for sale treatment. ASU 2017-05 reduces the number of potential accounting models that might apply and clarifies which model does apply in various circumstances. ASU 2017-05 will be effective for us on January 1, 2018 and is not expected to have a significant impact on our financial statements.
ASU 2017-08,“Receivables “Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20) - Premium Amortization on Purchased Callable Debt Securities.” ASU 2017-08 shortens the amortization period for certain callable debt securities held at a premium to require such premiums to be amortized to the earliest call date unless applicable guidance related to certain pools of securities is applied to consider estimated prepayments. Under prior guidance, entities were generally required to amortize premiums on individual, non-pooled callable debt securities as a yield adjustment over the contractual life of the security. ASU 2017-08 doesdid not change the accounting for callable debt securities held at a discount. We adopted ASU 2017-08 will be effective for us on January 1, 2019 with early adoption permitted. We are currently evaluating the potential impact of ASU 2017-08 on our financial statements.and recognized a cumulative effect adjustment reducing retained earnings by $12.6 million. See Note 1 - Significant Accounting Policies.
ASU 2017-09, “Compensation - Stock Compensation (Topic 718) - Scope of Modification Accounting.” ASU 2017-09 clarifies when changes to the terms or conditions of a share-based payment award must be accounted for as modifications. Under ASU 2017-09, an entity will not apply modification accounting to a share-based payment award if all of the following are the same immediately before and after the change: (i) the award's fair value, (ii) the award's vesting conditions and (iii) the award's classification as an equity or liability instrument. ASU 2017-09 will be effective for us on January 1, 2018 and is not expected to have a significant impact on our financial statements.
ASU 2017-12, “Derivatives and Hedging (Topic 815) - Targeted Improvements to Accounting for Hedging Activities.”ASU 2017-12 amends the hedge accounting recognition and presentation requirements in ASC 815 to improve the transparency and understandability of information conveyed to financial statement users about an entity’s risk management activities to better align the entity’s financial reporting for hedging relationships with those risk management activities and to reduce the complexity of and simplify the application of hedge accounting. ASU 2017-12 will bebecame effective for us on January 1, 2019 and isdid not expected to have a significant impact on our financial statements.
ASU 2018-16, “Derivatives and Hedging (Topic 815) - Inclusion of the Secured Overnight Financing Rate (“SOFR”) Overnight Index Swap (“OIS”) Rate as a Benchmark Interest Rate for Hedge Accounting Purposes.” The amendments in this update permit use of the OIS rate based on SOFR as a U.S. benchmark interest rate for hedge accounting purposes under Topic 815 in addition to the interest rates on direct U.S. Treasury obligations, the LIBOR swap rate, the OIS rate based on the Fed Funds Effective Rate and the Securities Industry and Financial Markets Association (“SIFMA”) Municipal Swap Rate. ASU 2018-16 became effective for us on January 1, 2019 and did not have a significant impact on our financial statements.



Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations
Financial Review
Cullen/Frost Bankers, Inc.
The following discussion should be read in conjunction with our consolidated financial statements, and notes thereto, for the year ended December 31, 20162018, and the other information included in the 20162018 Form 10-K. Operating results for the three and nine months ended September 30, 2017March 31, 2019 are not necessarily indicative of the results for the year ending December 31, 20172019 or any future period.
Dollar amounts in tables are stated in thousands, except for per share amounts.
Forward-Looking Statements and Factors that Could Affect Future Results
Certain statements contained in this Quarterly Report on Form 10-Q that are not statements of historical fact constitute forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 (the “Act”), notwithstanding that such statements are not specifically identified as such. In addition, certain statements may be contained in our future filings with the SEC, in press releases, and in oral and written statements made by us or with our approval that are not statements of historical fact and constitute forward-looking statements within the meaning of the Act. Examples of forward-looking statements include, but are not limited to: (i) projections of revenues, expenses, income or loss, earnings or loss per share, the payment or nonpayment of dividends, capital structure and other financial items; (ii) statements of plans, objectives and expectations of Cullen/Frost or its management or Board of Directors, including those relating to products, services or services;operations; (iii) statements of future economic performance; and (iv) statements of assumptions underlying such statements. Words such as “believes”, “anticipates”, “expects”, “intends”, “targeted”, “continue”, “remain”, “will”, “should”, “may” and other similar expressions are intended to identify forward-looking statements but are not the exclusive means of identifying such statements.
Forward-looking statements involve risks and uncertainties that may cause actual results to differ materially from those in such statements. Factors that could cause actual results to differ from those discussed in the forward-looking statements include, but are not limited to:
Local, regional, national and international economic conditions and the impact they may have on us and our customers and our assessment of that impact.
Volatility and disruption in national and international financial and commodity markets.
Government intervention in the U.S. financial system.
Changes in the mix of loan geographies, sectors and types or the level of non-performing assets and charge-offs.
Changes in estimates of future reserve requirements based upon the periodic review thereof under relevant regulatory and accounting requirements.
The effects of and changes in trade and monetary and fiscal policies and laws, including the interest rate policies of the Federal Reserve Board.
Inflation, interest rate, securities market and monetary fluctuations.
The effect of changes in laws and regulations (including laws and regulations concerning taxes, banking, securities and insurance) with which we and our subsidiaries must comply.
The soundness of other financial institutions.
Political instability.
Impairment of our goodwill or other intangible assets.
Acts of God or of war or terrorism.
The timely development and acceptance of new products and services and perceived overall value of these products and services by users.
Changes in consumer spending, borrowings and savings habits.
Changes in the financial performance and/or condition of our borrowers.
Technological changes.
The cost and effects of failure, interruption, or breach of security of our systems.
Acquisitions and integration of acquired businesses.
Our ability to increase market share and control expenses.
Our ability to attract and retain qualified employees.
Changes in the competitive environment in our markets and among banking organizations and other financial service providers.
The effect of changes in accounting policies and practices, as may be adopted by the regulatory agencies, as well as the Public Company Accounting Oversight Board, the Financial Accounting Standards Board and other accounting standard setters.
Changes in the reliability of our vendors, internal control systems or information systems.
Changes in our liquidity position.

Changes in our organization, compensation and benefit plans.
The costs and effects of legal and regulatory developments, the resolution of legal proceedings or regulatory or other governmental inquiries, the results of regulatory examinations or reviews and the ability to obtain required regulatory approvals.
Greater than expected costs or difficulties related to the integration of new products and lines of business.
Our success at managing the risks involved in the foregoing items.
Forward-looking statements speak only as of the date on which such statements are made. We do not undertake any obligation to update any forward-looking statement to reflect events or circumstances after the date on which such statement is made, or to reflect the occurrence of unanticipated events.
Application of Critical Accounting Policies and Accounting Estimates
We follow accounting and reporting policies that conform, in all material respects, to accounting principles generally accepted in the United States and to general practices within the financial services industry. The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. While we base estimates on historical experience, current information and other factors deemed to be relevant, actual results could differ from those estimates.
We consider accounting estimates to be critical to reported financial results if (i) the accounting estimate requires management to make assumptions about matters that are highly uncertain and (ii) different estimates that management reasonably could have used for the accounting estimate in the current period, or changes in the accounting estimate that are reasonably likely to occur from period to period, could have a material impact on our financial statements. Accounting policies related to the allowance for loan losses are considered to be critical as these policies involve considerable subjective judgment and estimation by management.
For additional information regarding critical accounting policies, refer to Note 1 - Summary of Significant Accounting Policies and Note 3 - Loans in the notes to consolidated financial statements and the sections captioned “Application of Critical Accounting Policies and Accounting Estimates” and “Allowance for Loan Losses” in Management’s Discussion and Analysis of Financial Condition and Results of Operations included in the 20162018 Form 10-K. There have been no significant changes in our application of critical accounting policies related to the allowance for loan losses since December 31, 20162018.
Overview
A discussion of our results of operations is presented below. Certain reclassifications have been made to make prior periods comparable. Taxable-equivalent adjustments are the result of increasing income from tax-free loans and investments by an amount equal to the taxes that would be paid if the income were fully taxable based on a 35%the applicable 21% federal tax rate in 2019 and 2018, thus making tax-exempt yields comparable to taxable asset yields.

Results of Operations
Net income available to common shareholders totaled $91.1$114.5 million, or $1.41 per diluted common share and $257.6 million, or $3.98$1.79 per diluted common share, for the three and nine months ended September 30, 2017March 31, 2019 compared to $78.2$104.5 million, or $1.24 per diluted common share, and $214.5 million, or $3.42$1.61 per diluted common share, for the three and nine months ended September 30, 2016.March 31, 2018.
Selected data for the comparable periods was as follows:
Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
Three Months Ended 
 March 31,
2017 2016 2017 20162019 2018
Taxable-equivalent net interest income$264,406
 $235,665
 $774,819
 $694,997
$271,179
 $252,536
Taxable-equivalent adjustment45,195
 41,158
 132,311
 120,264
24,710
 22,788
Net interest income219,211
 194,507
 642,508
 574,733
246,469
 229,748
Provision for loan losses10,980
 5,045
 27,358
 42,734
11,003
 6,945
Net interest income after provision for loan losses208,231
 189,462
 615,150
 531,999
235,466
 222,803
Non-interest income81,615
 82,114
 246,395
 256,274
96,785
 91,445
Non-interest expense186,823
 180,505
 562,789
 539,109
201,800
 196,611
Income before income taxes103,023
 91,071
 298,756
 249,164
130,451
 117,637
Income taxes9,892
 10,852
 35,131
 28,622
13,955
 11,157
Net income93,131
 80,219
 263,625
 220,542
116,496
 106,480
Preferred stock dividends2,016
 2,016
 6,047
 6,047
2,016
 2,016
Net income available to common shareholders$91,115
 $78,203
 $257,578
 $214,495
$114,480
 $104,464
Earnings per common share – basic$1.43
 $1.24
 $4.02
 $3.44
$1.80
 $1.63
Earnings per common share – diluted1.41
 1.24
 3.98
 3.42
1.79
 1.61
Dividends per common share0.57
 0.54
 1.68
 1.61
0.67
 0.57
Return on average assets1.19% 1.07% 1.14% 1.01%1.48% 1.36%
Return on average common equity11.71
 10.31
 11.44
 9.87
14.08
 13.62
Average shareholders’ equity to average assets10.63
 10.85
 10.43
 10.70
10.97
 10.46
Net income available to common shareholders increased $12.9$10.0 million, or 16.5%9.6%, for the three months ended September 30, 2017 and increased $43.1 million, or 20.1% for the nine months ended September 30, 2017March 31, 2019 compared to the same periodsperiod in 2016.2018. The increase during the three months ended September 30, 2017March 31, 2019 was primarily the result of a $24.7$16.7 million increase in net interest income and a $960 thousand decrease$5.3 million increase in non-interest income tax expense partly offset by a $6.3$5.2 million increase in non-interest expense, a $5.9$4.1 million increase in the provision for loan losses and a $499 thousand decrease in non-interest income. The increase during the nine months ended September 30, 2017 was primarily the result of a $67.8 million increase in net interest income and a $15.4 million decrease in the provision for loan losses partly offset by a $23.7 million increase in non-interest expense, a $9.9 million decrease in non-interest income and a $6.5$2.8 million increase in income tax expense.
Details of the changes in the various components of net income are further discussed below.
During the third quarter of 2017, our operations in our Houston and Corpus Christi market areas were disrupted by hurricane Harvey. As a result, we incurred certain additional expenses, as discussed below; lost potential revenue as a result of branch closures; and allocated a portion of our allowance for loan losses for probable losses related to the impact of the hurricane, as discussed below. While the ultimate impact of the hurricane on our operations is uncertain, we expect that it will be mitigated, at least in part, by insurance coverage and, based on the information available to us at this time, we do not expect any significant impact on our financial statements.
Net Interest Income
Net interest income is the difference between interest income on earning assets, such as loans and securities, and interest expense on liabilities, such as deposits and borrowings, which are used to fund those assets. Net interest income is our largest source of revenue, representing 72.3%71.8% of total revenue during the first ninethree months of 2017.2019. Net interest margin is the ratio of taxable-equivalent net interest income to average earning assets for the period. The level of interest rates and the volume and mix of earning assets and interest-bearing liabilities impact net interest income and net interest margin.
The Federal Reserve influences the general market rates of interest, including the deposit and loan rates offered by many financial institutions. Our loan portfolio is significantly affected by changes in the prime interest rate. The prime interest rate which is the rate offered on loans to borrowers with strong credit, remainedbegan 2018 at 3.50% during most of 2016. In December 2016, the prime rate increased 25 basis points to 3.75%4.50% and remained at that level until March 2017,2018, when the prime ratedit increased

another 25 basis points to 4.00%4.75%. In June 2017,During the remainder of 2018, the prime rate increased an additional 2575 basis points (25 basis points in each of June, September and December) to 4.25%end 2018 at 5.50%. The prime rate did not change during the first three months of 2019. Our loan portfolio is also impacted by changes in the London Interbank Offered Rate (LIBOR). At September 30, 2017,March 31, 2019, the one-month and three-month U.S. dollar LIBOR interest rates were 1.23%2.50% and 1.33%2.60%, respectively, while at September 30, 2016,March 31, 2018, the one-month and three-month U.S. dollar LIBOR interest rates were 0.53%1.89% and 0.85%2.31%, respectively. The effective federal funds rate, which is the cost of immediately available overnight funds, remainedbegan 2018 at 0.50% during most of 2016. In December 2016, the effective federal funds rate increased 25 basis points to 0.75%1.50% and remained at that level until March 2017,2018, when it increased 25 basis points to 1.75%. During the remainder of 2018 the effective federal funds rate increased another 2575 basis points (25 basis points in each of June, September, and December) to 1.00%end 2018 at 2.50%. In June 2017, theThe effective federal funds rate was increased an additional 25 basis points to 1.25%.did not change during the first three months of 2019.
We are primarily funded by core deposits, with non-interest-bearing demand deposits historically being a significant source of funds. This lower-cost funding base is expected to have a positive impact on our net interest income and net interest margin in

a rising interest rate environment. The Dodd-Frank Wall Street Reform and Consumer Protection Act (the “Dodd-Frank Act”) repealed the federal prohibitions on the payment of interest on demand deposits, thereby permitting depository institutions to pay interest on business transaction and other accounts beginning July 21, 2011. To date, we have not experienced any significant additional interest costs as a result of the repeal. However, in light of the aforementioned increases inas market interest rates in late July 2017,have increased, we have increased the interest rates we pay on most of our interest-bearing deposit products. See Item 3. Quantitative and Qualitative Disclosures About Market Risk elsewhere in this report for information about the expected impact of this legislation on our sensitivity to interest rates. Further analysis of the components of our net interest margin is presented below.
The following tables presenttable presents the changes in taxable-equivalent net interest income and identifies the changes due to differences in the average volume of earning assets and interest-bearing liabilities and the changes due to changes in the average interest rate on those assets and liabilities. The changes in net interest income due to changes in both average volume and average interest rate have been allocated to the average volume change or the average interest rate change in proportion to the absolute amounts of the change in each. The comparison between the periods includes an additional change factor that shows the effect of the difference in the number of days in each period for assets and liabilities that accrue interest based upon the actual number of days in the period, as further discussed below.
 Three Months Ended
 September 30, 2017 vs. September 30, 2016
 Increase (Decrease) Due to Change in  
 Rate Volume Number of Days Total
Interest-bearing deposits$6,472
 $217
 $
 $6,689
Federal funds sold and resell agreements75
 121
 
 196
Securities:       
Taxable(1,176) (1,518) 
 (2,694)
Tax-exempt(3,239) 7,234
 
 3,995
Loans, net of unearned discounts13,650
 12,298
 
 25,948
Total earning assets15,782
 18,352
 
 34,134
Savings and interest checking
 83
 
 83
Money market deposit accounts3,339
 4
 
 3,343
Time accounts147
 (13) 
 134
Public funds362
 (3) 
 359
Federal funds purchased and repurchase agreements467
 12
 
 479
Junior subordinated deferrable interest debentures181
 
 
 181
Subordinated notes payable and other notes819
 (5) 
 814
Total interest-bearing liabilities5,315
 78
 
 5,393
Net change$10,467
 $18,274
 $
 $28,741

Nine Months EndedThree Months Ended
September 30, 2017 vs. September 30, 2016March 31, 2019 vs. March 31, 2018
Increase (Decrease) Due to Change in  Increase (Decrease) Due to Change in 
Rate Volume Number of Days TotalRate Volume Total
Interest-bearing deposits$13,757
 $1,630
 $(41) $15,346
$6,265
 $(9,720) $(3,455)
Federal funds sold and resell agreements202
 148
 (1) 349
511
 316
 827
Securities:            
Taxable(4,440) (726) (204) (5,370)2,183
 1,938
 4,121
Tax-exempt(9,516) 32,818
 
 23,302
(1,719) 5,860
 4,141
Loans, net of unearned discounts28,934
 25,851
 (1,257) 53,528
23,348
 10,935
 34,283
Total earning assets28,937
 59,721
 (1,503) 87,155
30,588
 9,329
 39,917
Savings and interest checking
 117
 (3) 114
312
 23
 335
Money market deposit accounts3,391
 6
 (13) 3,384
12,835
 107
 12,942
Time accounts231
 (41) (3) 187
2,005
 167
 2,172
Public funds721
 (6) 
 715
870
 217
 1,087
Federal funds purchased and repurchase agreements638
 60
 (1) 697
4,296
 86
 4,382
Junior subordinated deferrable interest debentures497
 1
 
 498
356
 
 356
Subordinated notes payable and other notes1,875
 (137) 
 1,738

 
 
Total interest-bearing liabilities7,353
 
 (20) 7,333
20,674
 600
 21,274
Net change$21,584
 $59,721
 $(1,483) $79,822
$9,914
 $8,729
 $18,643
Taxable-equivalent net interest income for the three months ended September 30, 2017March 31, 2019 increased $28.7$18.6 million, or 12.2%, while taxable-equivalent net interest income for the nine months ended September 30, 2017 increased $79.8 million, or 11.5%7.4%, compared to the same periods in 2016. Taxable-equivalent net interest income for the nine months ended September 30, 2017 included 273 days compared to 274 days for the same period in 2016 as a result of the leap year.2018. The additional day added approximately $1.5 million to taxable-equivalent net interest income during the nine months ended September 30, 2016. Excluding the impact of the additional day results in an effective increase in taxable-equivalent net interest income of approximately $81.3 million during the nine months ended September 30, 2017. The increases in taxable-equivalent net interest income during the three and nine months ended September 30, 2017, excluding the impactfirst quarter of the aforementioned additional day during the nine months ended September 30, 2016, were2019 was primarily related to the impact of increases in the average volume of tax-exempt securities, loans and interest-bearing deposits as well as increases in the average yields on loans, and interest-bearing deposits partly offset by the impact of decreases in the average yields on tax-exempt and taxable securities and the impact ofcombined with increases in the average ratevolumes of loans, tax-exempt securities and taxable securities. The impact of these items was partly offset by increases in the average rates paid on interest-bearing liabilities. deposits and other borrowed funds and a decrease in the average volume of interest bearing deposits (primarily excess reserves held in an interest-bearing account at the Federal Reserve).
The average volume of interest-earning assets for the three months ended September 30, 2017 increased $1.3 billion, while the average volume of interest-earning assets during the nine months ended September 30, 2017 increased $1.7 billionMarch 31, 2019 decreased $48.0 million compared to the same periodsperiod in 2016.2018. The increasedecrease included a $1.9 billion decrease in average earning assets during the three months ended September 30, 2017, includedinterest-bearing deposits, federal funds sold and resell agreements partly offset by a $1.1 billion$910.6 million increase in average loans, a $377.0$558.2 million increase in average tax-exempt securities and a $161.3$373.4 million increase in average interest-bearing deposits partly offset by a $421.2 million decrease in average taxable securities. The increase in average earning assets during the nine months ended September 30, 2017, included an $821.8 million increase in average loans, a $648.9 million increase in average tax-exempt securities and a $384.9 million increase in average interest-bearing deposits partly offset by a $133.6 million decrease in average taxable securities.
The taxable-equivalent net interest margin increased 2027 basis points from 3.53%3.52% during the three months ended September 30, 2016March 31, 2018 to 3.73%3.79% during the three months ended September 30, 2017 and increased 13 basis points from 3.56% duringMarch 31, 2019. The increase in the nine months ended September 30, 2016 to 3.69% during the nine months ended September 30, 2017. The increases in thetaxable-equivalent net interest margin during the three and nine months ended September 30, 2017 werewas primarily due to increases in the average yield on interest earning assets. The average yield on interest-earning assets increased 28 basis points from 3.57% during the three months ended September 30, 2016 to 3.85% during the three months ended September 30, 2017 and increased 17 basis points from 3.60% during the nine months ended September 30, 2016 to 3.77% during the nine months ended September 30, 2017. The increases in the average yield on interest earning assets during the three and nine months ended September 30, 2017 were mostly duerelated to increases in the average yields on loans; interest-bearing deposits; federal funds sold and resell agreements; and taxable securities partly offset by increases in the average cost of interest-bearing deposits and loans.other borrowed funds and a decrease in the average yield on tax-exempt securities. The taxable-equivalent net interest margin was also positively impacted by a decrease in the relative proportion of interest-earning assets invested in lower-yielding interest-bearing deposits (primarily excess reserves held in an interest-bearing account at the Federal Reserve). The average taxable-equivalent yield on interest-earning assets isincreased 56 basis points from 3.71% during the three months ended March 31, 2018 to 4.27% during the three months ended March 31, 2019. The average taxable-equivalent yield on interest-earning assets was primarily impacted by the aforementioned changes in market interest rates, as well as changes in the volume and relative mix of interest-earning assets.assets and statutory tax rates.

The average taxable-equivalent yield on loans increased 3268 basis points from 4.00%4.65% during the first ninethree months of 2016ended March 31, 2018 to 4.32%5.33% during the first ninethree months of 2017.ended March 31, 2019. The average taxable-equivalent yield on loans was positively impacted by the increases in market interest rates compared to the same period in 2016, as discussed above. The average volume of loans duringfor the first ninethree months of 2017ended March 31, 2019 increased $821.8$910.6 million, or 7.1%6.8%, compared to the same period in 2016.2018. Loans made up approximately 43.8%49.1% of average interest-earning assets during the first ninethree months of 2017ended March 31, 2019 compared to 43.6%45.8% during the same period in 2016.

2018.
The average taxable-equivalent yield on securities was 3.96%3.37% during the first ninethree months of 2017, decreasing 5 basis points from 4.01%ended March 31, 2019, remaining relatively unchanged compared to the 3.36% during the first ninesame period in 2018. The average taxable-equivalent yield on securities during the three months ended March 31, 2019 compared to the same period in 2018 was positively impacted by increases in the average volume of 2016. Despite the fact thattax-exempt and taxable securities and an increase in the average yield on taxable securities decreased 12 basis points from 2.02% during the first nine months of 2016 to 1.90% during the first nine months of 2017 andbut was negatively impacted by a decrease in the average yield on tax-exempt securities decreased 19 basis point from 5.58% during the first nine months of 2016 to 5.39% during the first nine months of 2017, the overallsecurities. The average yield on taxable securities only decreased 5increased 20 basis points because of a higher proportion offrom 1.99% during the three months ended March 31, 2018 to 2.19% during the three months ended March 31, 2019. The average securities invested in higher yieldingtaxable-equivalent yield on tax-exempt securities decreased 9 basis points from 4.12% during the first ninethree months of 2017 comparedended March 31, 2018 to 4.03% during the same period in 2016.three months ended March 31, 2019. Tax exempt securities made up approximately 58.8%64.4% of total average securities during the first ninethree months of 2017,ended March 31, 2019, compared to 55.9%64.8% during the same period in 2016.2018. The average volume of total securities during the first ninethree months of 2017ended March 31, 2019 increased $515.3$931.7 million, or 4.3%7.9%, compared to the same period in 2016.2018. Securities made up approximately 44.1% of average interest-earning assets during the first ninethree months of 2017ended March 31, 2019 compared to 45.1%40.8% during the same period in 2016.2018.
Average interest-bearing deposits, federal funds sold and resell agreements and interest-bearing deposits duringfor the first ninethree months of 2017 increased $407.3 millionended March 31, 2019 decreased $1.9 billion, or 48.9%, compared to the same period in 2016.The increase in average2018. Interest-bearing deposits, federal funds sold and resell agreements and interest-bearing deposits was primarily related to growth in average deposits. Federal funds sold, resell agreements and interest-bearing deposits made up approximately 12.1%6.8% of average interest-earning assets during the first ninethree months of 2017ended March 31, 2019 compared to 11.3%13.4% during the three months ended March 31, 2018. The decrease in the average volume of interest-bearing deposits, federal funds sold and resell agreements was primarily due to a decrease in the average volume of our excess reserves held in an interest-bearing account at the Federal Reserve during the first quarter of 2019 compared to the same period in 2018 as such funds were invested in higher yielding loans and securities. The volume of interest-bearing deposits, federal funds sold and resell agreements was also impacted by a decrease in the average volume of deposits during the first quarter of 2019 compared to the same period in 2018. The combined average yield on interest-bearing deposits, federal funds sold and resell agreements was 2.51% during the three months ended March 31, 2019 compared to 1.56% during the same period in 2016. The combined average yield on federal funds sold, resell agreements and interest-bearing deposits was 1.07% during the first nine months of 2017 compared to 0.51% during the same period in 2016.2018. As discussed above, the effective federal funds rate began 2018 at 1.50% and subsequently increased from 0.50%100 basis points (25 basis points in each of March, June, September and December) to 0.75% in December 2016, increased from 0.75% to 1.00% inend 2018 at 2.50%, where it remained through March 2017 and increased from 1.00% to 1.25% in June 2017.31, 2019.
The average rate paid on interest-bearing liabilities was 0.13%0.81% during the first ninethree months of 2017,ended March 31, 2019 increasing 548 basis points from 0.08%0.33% during the same period in 2016.2018. Average deposits increased $1.5 billiondecreased $317.3 million, or 1.20%, during the first ninethree months of 2017ended March 31, 2019 compared to the same period in 2016. Average non-interest-bearing2018 and included a $779.8 million decrease in average non-interest bearing deposits for the first nine months of 2017 increased $832.2partly offset by a $462.5 million compared to the same periodincrease in 2016, while average interest-bearing deposits for the first nine months of 2017 increased $699.7 million compared to the same period in 2016.deposits. The ratio of average interest-bearing deposits to total average deposits was 58.3%61.0% during the first ninethree months of 2017ended March 31, 2019 compared to 59.1%58.5% during the same period in 2016.of 2018. The average cost of deposits is primarily impacted by changes in market interest rates as well as changes in the volume and relative mix of interest-bearing deposits. The average cost of interest-bearing deposits and total deposits was 0.09%0.69% and 0.05%0.42%, respectively, during the first ninethree months of 2017ended March 31, 2019 compared to 0.05%0.28% and 0.03%0.16%, respectively, during the first ninethree months of 2016.ended March 31, 2018. The average cost of deposits during 20172019 was impacted by the aforementioned increases in the interest rates paidwe pay on most of our interest-bearing deposit products duringas a result of the third quarter.aforementioned increases in market interest rates and market competition.
Our net interest spread, which represents the difference between the average rate earned on earning assets and the average rate paid on interest-bearing liabilities, was 3.64%3.46% during the first ninethree months of 2017ended March 31, 2019 compared to 3.52%3.38% during the same period in 2016.2018. The net interest spread, as well as the net interest margin, will be impacted by future changes in short-term and long-term interest rate levels, as well as the impact from the competitive environment. A discussion of the effects of changing interest rates on net interest income is set forth in Item 3. Quantitative and Qualitative Disclosures About Market Risk included elsewhere in this report.
Our hedging policies permit the use of various derivative financial instruments, including interest rate swaps, swaptions, caps and floors, to manage exposure to changes in interest rates. Details of our derivatives and hedging activities are set forth in Note 98 - Derivative Financial Instruments in the accompanying notes to consolidated financial statements included elsewhere in this report. Information regarding the impact of fluctuations in interest rates on our derivative financial instruments is set forth in Item 3. Quantitative and Qualitative Disclosures About Market Risk included elsewhere in this report.

Provision for Loan Losses
The provision for loan losses is determined by management as the amount to be added to the allowance for loan losses after net charge-offs have been deducted to bring the allowance to a level which, in management’s best estimate, is necessary to absorb inherent losses within the existing loan portfolio. The provision for loan losses totaled $11.0 million and $27.4for the three months ended March 31, 2019 compared to $6.9 million for the three and nine months ended September 30, 2017 compared to $5.0 million and $42.7 million for the three and nine months ended September 30, 2016.March 31, 2018. See the section captioned “Allowance for Loan Losses” elsewhere in this discussion for further analysis of the provision for loan losses.

Non-Interest Income
The components of non-interest income were as follows:
Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
Three Months Ended 
 March 31,
2017 2016 2017 20162019 2018
Trust and investment management fees$27,493
 $26,451
 $81,690
 $77,806
$31,697
 $29,587
Service charges on deposit accounts20,967
 20,540
 62,934
 60,769
20,790
 20,843
Insurance commissions and fees10,892
 11,029
 34,441
 35,812
18,406
 15,980
Interchange and debit card transaction fees5,884
 5,435
 17,150
 15,838
3,280
 3,158
Other charges, commissions and fees10,493
 10,703
 29,983
 29,825
9,062
 9,007
Net gain (loss) on securities transactions(4,867) (37) (4,917) 14,866

 (19)
Other10,753
 7,993
 25,114
 21,358
13,550
 12,889
Total$81,615
 $82,114
 $246,395
 $256,274
$96,785
 $91,445
Total non-interest income for the three and nine months ended September 30, 2017 decreased $499 thousand, or 0.6% and decreased $9.9March 31, 2019 increased $5.3 million, or 3.9%5.8%, compared to the same periods in 2016, respectively. Excluding the impact of the net gain (loss) on securities transactions, total non-interest income effectively increased $4.3 million, or 5.3%, and $9.9 million, or 4.1%, respectively, for the three and nine months ended September 30, 2017 compared to the same period in 2016.2018. Changes in the various components of non-interest income are discussed in more detail below.
Trust and Investment Management Fees. Trust and investment management fees for the three and nine months ended September 30, 2017March 31, 2019 increased $1.0$2.1 million, or 3.9%, and increased $3.9 million, or 5.0%7.1%, compared to the same periodsperiod in 2016, respectively.2018. Investment fees are the most significant component of trust and investment management fees, making up approximately 83.5%83.2% and 81.6%84.0% of total trust and investment management fees for the first ninethree months of 20172019 and 2016,2018, respectively. Investment and other custodial account fees are generally based on the market value of assets within a trust account. Volatility in the equity and bond markets impacts the market value of trust assets and the related investment fees.
The increase in trust and investment management fees during the three and nine months ended September 30, 2017March 31, 2019 compared to the same periodperiods in 20162018 was primarily the result of increases in trust investment fees (up $1.6 million$1.5 million) and $4.7 million, respectively)increases in oil and gas fees (up $598 thousand). The increase in trust investment fees during 20172019 was due to higher average equity valuations.valuations and an increase in the number of accounts. The increasesincrease in trust investment fees were partly offset by decreases in estate fees (down $212 thousand and $537 thousand during the three and nine months ended September 30, 2017, respectively) and oil and gas fees (down $294 thousandduring 2019 was related to energy prices and $159 thousand during the three and nine months ended September 30, 2017, respectively).new business, partly driven by enhancements to our service offering.
At September 30, 2017,March 31, 2019, trust assets, including both managed assets and custody assets, were primarily composed of equity securities (49.6%(50.0% of assets), fixed income securities (39.1%(37.1% of assets) and cash equivalents (6.9%(7.3% of assets). The estimated fair value of these assets was $31.0$35.0 billion (including managed assets of $13.9$15.0 billion and custody assets of $17.2$20.0 billion) at September 30, 2017,March 31, 2019, compared to $29.3$33.3 billion (including managed assets of $13.4$14.7 billion and custody assets of $15.9$18.7 billion) at December 31, 20162018 and $29.7$32.9 billion (including managed assets of $13.3$14.2 billion and custody assets of $16.4$18.7 billion) at September 30, 2016.March 31, 2018.
Service Charges on Deposit Accounts. Service charges on deposit accounts for the three months ended September 30, 2017 increased $427March 31, 2019 decreased $53 thousand, or 2.1%0.3%, compared to the same period in 2016.2018. The increasedecrease was primarily duerelated to increases in consumer service charges (up $429 thousand) and overdraft/insufficient funds charges on consumer and commercial accounts (up $315 thousand and $62 thousand, respectively) partly offset by a decrease in commercial service charges (down $368$875 thousand). Service charges on deposit accounts for the nine months ended September 30, 2017 increased $2.2 million, or 3.6%, compared to the same period in 2016. The increase was primarily due to mostly offset by increases in overdraft/insufficient funds charges on consumer and commercial accounts (up $1.6 million$693 thousand and $361$85 thousand, respectively) and consumer service charges (up $451$57 thousand) partly offset by a. The decrease in commercial service charges (down $221 thousand).was primarily due to a decrease in commercial deposit volumes during the first quarter of 2019 compared to the same period in 2018. Overdraft/insufficient funds charges totaled $8.7$9.6 million ($6.87.4 million consumer and $2.0$2.2 million commercial) during the three months ended September 30, 2017March 31, 2019 compared to $8.4$8.8 million ($6.56.8 million consumer and $1.9$2.1 million commercial) during the same period in 2016. Overdraft/2018. The increase in overdraft/insufficient funds charges totaled $25.9 million ($20.0 million consumer and $5.9 million commercial)was primarily due to increased transactions volumes during the nine months ended September 30, 2017first quarter of 2019 compared to $23.9 million ($18.4 million consumer and $5.5 million commercial) during the same period in 2016.2018.
Insurance Commissions and Fees. Insurance commissions and fees for the three months ended September 30, 2017 decreased $137 thousand,March 31, 2019 increased $2.4 million, or 1.2%15.2%, compared to the same period in 2016.2018. The decreaseincrease was related to increases in commission income (up $2.6 million) partly offset by a decrease in contingent income (down $212$189 thousand) partly offset by an. The increase in commission income (up $75 thousand). Insuranceduring the three months ended March 31, 2019 was primarily related to increases in benefit plan commissions; commissions on property; and casualty policies and life insurance commissions. The increases in benefit plan commissions and fees for the nine months ended September 30, 2017 decreased $1.4 million, or 3.8%, compared to the same period in 2016. The decrease wasproperty and

casualty commissions were related to a decrease in contingent income (down $2.7 million) partly offset by anincreased business volumes and market rates. The increase in commission income (up $1.3 million).life insurance commissions was related to increased business volumes. Insurance commissions and fees include contingent income totaling $358 thousand$3.2 million during the three months ended March 31, 2019 and $3.4 million during the three and nine months ended September 30, 2017, respectively, and $570 thousand and $6.1 million during the same periodsperiod in 2016.2018. Contingent income primarily consists of amounts received from various property and casualty insurance carriers related to the loss performance of insurance policies previously placed. These performance related contingent payments are seasonal in nature and are mostly received during the first quarter of each year. This performance related contingent income totaled $2.1$2.6 million and $4.6$2.9 million during the ninethree months ended September 30, 2017March 31, 2019 and 2016,2018, respectively. The decrease in performance related contingent income during 20172019 was related to a lack oflower growth within the portfolio and a deteriorationpartly offset by the impact of improvement in the loss performance of insurance policies previously placed. Contingent income also includes amounts received from various benefit plan insurance companies related to the volume of business generated and/or the subsequent retention of such business. This benefit plan related contingent income totaled $311$603 thousand and $1.3 million during the three and nine months ended September 30, 2017March 31, 2019, and $417$552 thousand and $1.5 million during the three and nine months ended September 30, 2016. The increasessame period in commission income during the three and nine months ended September 30, 2016 were primarily related to increases in benefit plan commissions due to increased business volumes partly offset by decreases in commissions on property and casualty policies.2018.
Interchange and Debit Card Transaction Fees. Interchange fees, or “swipe” fees, are charges that merchants pay to us and other card-issuing banks for processing electronic payment transactions. Interchange and debit card transaction fees consist of income from check card usage, point of sale income from PIN-based debit card transactions and ATM service fees. Interchange and debit card transaction fees are reported net of related network costs. A comparison of gross and net interchange and debit card transaction fees for the threereported periods is presented in the table below:
 Three Months Ended 
 March 31,
 2019 2018
Income from debit card transactions$5,405
 $5,124
ATM service fees981
 947
Gross interchange and debit card transaction fees6,386
 6,071
Network costs3,106
 2,913
Net interchange and debit card transaction fees$3,280
 $3,158
The increase in interchange and nine months ended September 30, 2017 increased $449 thousand, or 8.3%, and $1.3 million, or 8.3%, compared to the three and nine months ended September 30, 2016. The increases were primarily due to increases in income from debit card transactions (up $381 thousand and $1.0 million for the three and nine months ended September 30, 2017, respectively) and ATM servicetransaction fees (up $68 thousand and $267 thousand for the three and nine months ended September 30, 2017, respectively). The increases wereduring 2019, on a net basis, was primarily related to increased transaction volumes.
Federal Reserve rules applicable to financial institutions that have assets of $10 billion or more provide that the maximum permissible interchange fee for an electronic debit transaction is the sum of 21 cents per transaction and 5 basis points multiplied by the value of the transaction. An upward adjustment of no more than 1 cent to an issuer's debit card interchange fee is allowed if the card issuer develops and implements policies and procedures reasonably designed to achieve certain fraud-prevention standards. The Federal Reserve also has rules governing routing and exclusivity that require issuers to offer two unaffiliated networks for routing transactions on each debit or prepaid product.
Other Charges, Commissions and Fees. Other charges, commissions and fees for the three months ended September 30, 2017 decreased $210March 31, 2019 increased $55 thousand, or 2.0%0.6%, compared to the same period in 2016.2018. The decrease includedincrease was primarily related to increases in income from the sale of life insurance and money market accounts (up $375 thousand and $316 thousand, respectively) mostly offset by decreases in human resources consulting fee income (down $160 thousand) and income from corporate finance and capital market advisory services (down $109 thousand), among other things. These items were partly offset by an increase in income related to the sale of mutual funds (up $128and annuities (down $276 thousand and $195 thousand, respectively) and brokerage commissions (down $196 thousand), among other things. Other charges, commissions and fees for the nine months ended September 30, 2017 increased $158 thousand, or 0.5%, compared to the same period in 2016. The increase included increases in income related to the sale of mutual funds (up $911 thousand) and wire transfer fees (up $235 thousand), among other things. These items were partly offset by decreases in human resources consulting fee income (down $486 thousand) and income from corporate finance and capital market advisory services (down $476 thousand), among other things. Human resources consulting fee income decreased as we no longer provide these services. Changes in the other aforementioned categories of other charges, commissions and fees were due to fluctuations in business volumes..
Net Gain/Loss on Securities Transactions. During the ninethree months ended September 30, 2017,March 31, 2019, and 2018, we sold certain available-for-sale U.S Treasury securities with an amortized costcosts totaling $8.2$944.9 million and $3.0 billion, andrespectively. No significant net gain or loss was realized on the 2019 sales while we realized a net loss of $50totaling $19 thousand on thosethe 2018 sales. The sales were primarily related to securities purchased during 2017 and subsequently sold in the same period of their purchase in connection with our tax planning strategies related to the Texas franchise tax. The gross proceeds from the sales of these securities outside of Texas are included in total revenues/receipts from all sources reported for Texas franchise tax purposes, which results in a reduction in the overall percentage of revenues/receipts apportioned to Texas and subjected to taxation under the Texas franchise tax. We also sold, during the third quarter of 2017, certain other available-for-sale U.S. Treasury securities with an amortized cost totaling $751.4 million and realized a net loss of $4.9 million on those sales. These securities were sold with the intent to reinvest the sales proceeds in higher yielding debt securities and other investments.
During the nine months ended September 30, 2016, we sold certain available-for sale U.S. Treasury securities with an amortized cost totaling $8.0 billion and realized a net loss of $37 thousand on those sales. The sales were primarily related to securities purchased during 2016 and subsequently sold in connection with our aforementioned tax planning strategies related to the Texas franchise tax. We also sold certain other available-for-sale U.S. Treasury securities with an amortized cost totaling $749.5 million and realized a net gain of $2.8 million on those sales. The securities sold were due to mature during 2016. Most of the proceeds from the sale of these securities were reinvested into U.S. Treasury securities having comparable yields, but longer-terms. During the nine months ended September 30, 2016, we also sold certain municipal securities that were classified as both available for

sale and held to maturity due to a significant deterioration in the creditworthiness of the issuers. These securities had a total amortized cost of $431.4 million and we realized a gain of $12.1 million on those sales. Refer to our 2016 Form 10-K for additional information related to these sales.
Other Non-Interest Income. Other non-interest income for the three months ended September 30, 2017March 31, 2019 increased $2.8 million,$661 thousand, or 34.5%5.1%, compared to the same period in 2016.2018. The increase during the three months ended March 31, 2019 was primarily related to increases in sundry and other miscellaneous income (up $1.1 million), income from customer derivative and trading activities (up $935 thousand), gains on the sale of foreclosed and other assets (up $724$802 thousand) and income from customer foreign currency transactionspublic finance underwriting fees (up $248$535 thousand). Sundry and other miscellaneous income during the three months ended September 30, 2017 included $1.2 million related to the collection of amounts charged-off partly offset by Western National Bank prior to our acquisition and $426 thousand related to recoveries of prior write-offs, among other things, while sundry and other miscellaneous income during the same period in 2016 included $453 thousand related to recoveries of prior write-offs, among other things. The fluctuationsa decrease in income from customer derivative and trading activities (down $889 thousand). Sundry income during the three months ended March 31, 2019 included $931 thousand related to the recovery of interest written-off prior to 2019 and $250 thousand related to a settlement, among other things. The fluctuations in public finance underwriting fees income and income from customer foreign currency transactionsderivative and trading activities during the three months ended March 31, 2019 were primarily related to changes in business volumes. During the third quarter of 2017,Other non-interest income also included gains on the sale of foreclosedvarious branch and other assets included $700 thousand related to amortization ofoperational facilities totaling $4.0 million during the deferred gain on our headquarters building, which we sold in December 2016.
Other non-interest income for the ninethree months ended September 30, 2017 increased $3.8March 31, 2019 and $3.7 million or 17.6%, compared to the same period in 2016. The increase was primarily related to increases in gains on the sale of foreclosed and other assets (up $1.5 million), sundry and other miscellaneous income (up $1.5 million), income from customer foreign currency transactions (up $497 thousand) and income from customer derivative and trading activities (up $422 thousand), among other things, partly offset by decreases in lease rental income (down $384 thousand) and earnings on the cash surrender value of life insurance policies (down $311 thousand), among other things. Sundry income during the nine months ended September 30, 2017 included the aforementioned $1.2 million related to the collection of amounts charged-off by Western National Bank prior to our acquisition, $864 thousand related to the settlement of a non-solicitation agreement and $541 thousand related to recoveries of prior write-offs among other things, while sundry and other miscellaneous income during the same period in 2016 included $1.1 million related to recoveries of prior write-offs, among other things. The fluctuations in income from customer foreign currency transactions and income from customer derivative and trading activities were primarily related to changes in business volumes. During the first nine months of 2017, gains on the sale of foreclosed and other assets included $2.2 million related to amortization of the aforementioned deferred gain on our headquarters building.2018.

Non-Interest Expense
The components of non-interest expense were as follows:
Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
Three Months Ended 
 March 31,
2017 2016 2017 20162019 2018
Salaries and wages$84,388
 $79,411
 $247,895
 $236,814
$92,476
 $86,683
Employee benefits17,730
 17,844
 57,553
 55,861
23,526
 21,995
Net occupancy19,391
 18,202
 57,781
 53,631
19,267
 19,740
Furniture and equipment18,743
 17,979
 54,983
 53,474
Technology, furniture and equipment21,664
 19,679
Deposit insurance4,862
 4,558
 15,347
 12,412
2,808
 4,879
Intangible amortization405
 586
 1,301
 1,869
325
 388
Other41,304
 41,925
 127,929
 125,048
41,734
 43,247
Total$186,823
 $180,505
 $562,789
 $539,109
$201,800
 $196,611
Total non-interest expense for the three and nine months ended September 30, 2017March 31, 2019 increased $6.3$5.2 million, or 3.5% and $23.7 million, or 4.4%2.6%, compared to the same periodsperiod in 2016.2018. Changes in the various components of non-interest expense are discussed below.
Salaries and Wages. Salaries and wages for the three and nine months ended September 30, 2017March 31, 2019 increased $5.0$5.8 million, or 6.3%, and $11.1 million, or 4.7%6.7%, compared to the same periodsperiod in 2016.2018. The increase was primarily related to an increase in salaries, due to an increase in the number of employees and normal annual merit and market increases, as well as increases in stockincentive compensation and incentivestock compensation. Salaries and wages during the three and nine months ended September 30, 2017 also included approximately $1.2 million in severance expense primarily related to the closure of certain branch locations.
Employee Benefits. Employee benefits expense for the three months ended September 30, 2017 decreased $114 thousand,March 31, 2019 increased $1.5 million, or 0.6%7.0%, compared to the same period in 2016.2018. The decreaseincrease was primarily due to decreasesincreases in medical insurancebenefits expense (down $502(up $654 thousand), expenses related to our defined benefit retirement plans (down $302(up $585 thousand) and other employee benefits (down $120 thousand) partly offset by an increase in expenses related to our 401(k) and profit sharing plansplan (up $851$387 thousand). Employee

benefits expense for the nine months ended September 30, 2017 increased $1.7 million, or 3.0%, compared to the same period in 2016. The increase was primarily due to increases in expenses related to our 401(k) and profit sharing plans (up $1.6 million) and payroll taxes (up $1.1 million) partly offset by a decrease in expenses related to our defined benefit retirement plans (down $1.1 million).
During the three and nine months ended September 30, 2017,March 31, 2019, we recognized a combined net periodic pension expense of $125$331 thousand and $376 thousand, respectively, related to our defined benefit retirement plans compared to a combined net periodic pension expensebenefit of $427$254 thousand and $1.4 million during the same periodsperiod in 2016. Net periodic pension expense during the nine months ended September 30, 2016 included $187 thousand in supplemental executive retirement plan (“SERP”) settlement costs related to the retirement of a former executive officer.2018. Our defined benefit retirement and restoration plans were frozen effective as of December 31, 2001 and were replaced by a profit sharing plan.plan (which was merged with and into our 401(k) plan during 2019). Management believes these actions helped to reduce the volatility in retirement plan expense. However, we still have funding obligations related to the defined benefit and restoration plans and could recognize retirement expense related to these plans in future years, which would be dependent on the return earned on plan assets, the level of interest rates and employee turnover. See Note 12 - Defined Benefit Plans for additional information related to our net periodic pension benefit/cost.
Net Occupancy. Net occupancy expense for the three and nine months ended September 30, 2017 increased $1.2 million,March 31, 2019 decreased $473 thousand, or 6.5%, and $4.2 million, or 7.7%2.4%, compared to the same periodsperiod in 2016.2018. The increasedecrease during the three months ended September 30, 2017March 31, 2019 was primarily related to decreases in property taxes (down $753 thousand), repairs and maintenance/service contracts expense (down $220 thousand) and utilities expense (down $220 thousand) partly offset by increases in lease expense (up $782 thousand), property taxes (up $338 thousand), utilities expense (up $140$465 thousand) and depreciation on leasehold improvements (up $125$230 thousand) partly offset by a decrease in building depreciation (down $372 thousand). The increase during the nine months ended September 30, 2017 was primarily related to increases in lease expense (up $2.6 million), property taxes (up $1.0 million), depreciation on leasehold improvements (up $604 thousand), repairs and maintenance/service contracts expense (up $535 thousand) and utilities expense (up $336 thousand) partly offset by a decrease in building depreciation (down $1.1 million). The increases in lease expense and the decreases in building depreciation during the reported periods were primarily related to the sale and lease back of our headquarters building in December 2016, as more fully discussed in our 2016 Form 10-K.
Technology, Furniture and Equipment. Furniture Technology, furniture and equipment expense for the three and nine months ended September 30, 2017March 31, 2019 increased $764 thousand, or 4.2%, and $1.5$2.0 million, or 2.8%10.1%, compared to the same periodsperiod in 2016.2018. The increases wereincrease was primarily related to increases in software maintenance (up $974 thousand and $2.3 million for the three and nine months ended September 30, 2017, respectively) and$1.6 million), depreciation on furniture and equipment (up $198 thousand$288 thousand) and $1.4 million for the three and nine months ended September 30, 2017, respectively) partly offset by a decrease in equipment rental expense (down $576 thousand and $1.6 million for the three and nine months ended September 30, 2017, respectively), and, for the nine months ended September 30, 2017, a decrease in service contracts (down $413software amortization (up $207 thousand), among other things..
Deposit Insurance. Deposit insurance expense totaled $4.9 million and $15.3$2.8 million for the three and nine months ended September 30, 2017March 31, 2019 compared to $4.6 million and $12.4$4.9 million for the three and nine months ended September 30, 2016. DepositMarch 31, 2018. The decrease in deposit insurance expense during 2019 was impacted by an increase in assets and, during the nine-months ended September 30, 2017, an increase in the overall assessment rate. The increase in the assessment rate was partlyprimarily related to a newdecrease in our base assessment rate and the termination of the quarterly Deposit Insurance Fund surcharge that became applicable duringin the thirdfourth quarter of 2016. 2018, as further discussed below.
In August 2016, the Federal Deposit Insurance Corporation (“FDIC”) announced that the Deposit Insurance Fund (“DIF”) reserve ratio had surpassed 1.15% as of June 30, 2016. As a result, beginning in the third quarter of 2016, the range of initial assessment rates for all institutions was adjusted downward and institutions with $10 billion or more in assets were assessed a quarterly surcharge. The quarterly surcharge will continue to be assessed until such timewas terminated in the fourth quarter of 2018 as the Deposit Insurance Fund reserve ratio reachesas of September 30, 2018 exceeded the statutory minimum of 1.35% required by the Dodd-Frank Wall Street Reform and Consumer Protection Act.

Intangible Amortization.Amortization. Intangible amortization is primarily related to core deposit intangibles and, to a lesser extent, intangibles related to customer relationships and non-compete agreements. Intangible amortization for the three and nine months ended September 30, 2017March 31, 2019 decreased $181$63 thousand, or 30.9%16.2%, and $568 thousand, or 30.4%, respectively, compared to the same periodsperiod in 2016.2018. The decrease in amortization was primarily related to the completion of amortization of certain previously recognized intangible assets as well as a reduction in the annual amortization rate of certain previously recognized intangible assets as we use an accelerated amortization approach which results in higher amortization rates during the earlier years of the useful lives of intangible assets.
Other Non-Interest Expense. Other non-interest expense for the three months ended September 30, 2017March 31, 2019 decreased $621 thousand,$1.5 million, or 1.5%3.5%, compared to the same period in 2016.2018. The decrease included decreases in check carddonations expense (down $1.2$3.7 million), sundry and other miscellaneous expenses (down $1.9 million) and professional services expense (down $711$960 thousand), regulatory examination fees (down $198 thousand) and losses on the sale/write-downamong other things. Donations expense during 2018 was impacted by a significant contribution to our charitable foundation. Professional services expense during 2018 was impacted by a data security incident which resulted in unauthorized access to a third-party lockbox software program used by certain of foreclosed and other assets (down $170 thousand). Theseour commercial lockbox customers to store digital images. The aforementioned items were partly offset by increases in guard servicesadvertising/promotions expense, partly related to new sponsorship arrangements (up $580 thousand)$3.5 million), the provision for losses on unfunded loan commitments (up$250 thousand), business development expensesand platform/management fees related to Frost Investment Advisors and Frost Investment Services (up $207 thousand), point-of-sale related expenses (up $205 thousand), platform fees associated with our managed mutual funds (up $198 thousand) and travel/meals and entertainment expense (up $194$489 thousand), among other things. Other non-interest expense for the nine months ended September 30, 2017 increased

$2.9 million, or 2.3%, compared to the same period in 2016. The increase included increases in guard services expense (up $1.1 million), fraud losses (up $924 thousand), travel/meals and entertainment expense (up $828 thousand), advertising/promotions expense (up $688 thousand) and outside computer services expense (up $760 thousand), among other things. These items were partly offset by a decrease in check card expense (down $1.8 million), among other things. Guard services expense during the three and nine months ended September 30, 2017 was impacted by the effects of hurricane Harvey during the third quarter. The increase in fraud losses was primarily related to check cards, ATMs and checks.
Results of Segment Operations
Our operations are managed along two primary operating segments: Banking and Frost Wealth Advisors. A description of each business and the methodologies used to measure financial performance is described in Note 1615 - Operating Segments in the accompanying notes to consolidated financial statements included elsewhere in this report. Net income (loss) by operating segment is presented below:
Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
Three Months Ended 
 March 31,
2017 2016 2017 20162019 2018
Banking$88,368
 $76,347
 $250,766
 $210,454
$112,917
 $103,641
Frost Wealth Advisors6,417
 4,797
 17,990
 13,809
6,400
 5,634
Non-Banks(1,654) (925) (5,131) (3,721)(2,821) (2,795)
Consolidated net income$93,131
 $80,219
 $263,625
 $220,542
$116,496
 $106,480
Banking
Net income for the three and nine months ended September 30, 2017March 31, 2019 increased $12.0$9.3 million, or 15.7%, and $40.3 million, or 19.2%9.0%, compared to the same periodsperiod in 2016.2018. The increase during the three months ended September 30, 2017March 31, 2019 compared to the same period in 2018 was primarily the result of a $24.0 million increaseincreases in net interest income (up $17.1 million) and a $1.8 million decrease innon-interest income tax expense(up $3.0 million) partly offset by a $6.1 million increaseincreases in non-interest expense a $5.9 million increase in(up $4.2 million), the provision for loan losses (up $4.1 million) and a $1.8 million decrease in non-interest income. The increase during the nine months ended September 30, 2017 was primarily the result of a $65.0 million increase in net interest income and a $15.4 million decrease in the provision for loan losses partly offset by a $20.2 million increase in non-interest expense, a $15.4 million decrease in non-interest income and a $4.5 million increase in income tax expense.expense (up $2.6 million).
Net interest income for the three and nine months ended September 30, 2017March 31, 2019 increased $24.0$17.1 million, or 12.5%, and $65.0 million, or 11.4%7.4%, compared to the same periods in 2016. Taxable-equivalent net interest income for the first nine months of 2017 included 273 days compared to 274 days for the same period in 2016 as a result of the leap year.2018. The additional day added approximately $1.5 million to taxable-equivalent net interest income during the first nine months of 2016. Despite the effect of this additional day during 2016, net interest incomeincrease during the three and nine months ended September 30, 2017 increased dueMarch 31, 2019 was primarily related to the impact of increases in the average volume of tax-exempt securities, loans and interest-bearing deposits as well as increases in the average yields on loans, and interest-bearing deposits partly offset by the impact of decreases in the average yields on tax-exempt and taxable securities combined with the impact of increases in the average ratevolumes of loans, tax-exempt securities and taxable securities. The impact of these items was partly offset by increases in the average rates paid on interest-bearing liabilities.deposits and other borrowed funds and a decreases in the average volume of interest bearing deposits (primarily excess reserves held in an interest-bearing account at the Federal Reserve). See the analysis of net interest income included in the section captioned “Net Interest Income” included elsewhere in this discussion.
The provision for loan losses for the three and nine months ended September 30, 2017March 31, 2019 totaled $11.0 million and $27.4 million compared to $5.0 million and $42.7$6.9 million for the same periodsperiod in 2016.2018. See the analysis of the provision for loan losses included in the section captioned “Allowance for Loan Losses” included elsewhere in this discussion.
Non-interest income for the three months ended September 30, 2017 decreased $1.8March 31, 2019 increased $3.0 million, or 3.5%, while non-interest income for the nine months ended September 30, 2017 decreased $15.4 million, or 9.2%5.2%, compared to the same periodsperiod in 2016. Both the three and nine months ended September 30, 2017 included a net loss on securities transactions of $4.9 million compared to a net loss of $37 thousand2018. The increase during the three months ended September 30, 2016 and a net gain of $14.9 million during the nine months ended September 30, 2016. See the analysis of these net gains and losses included in the section captioned “Net Gain/Loss on Securities Transactions” included elsewhere in this discussion. Excluding the impact of the net gains or losses on securities transactions, total non-interest income during the three and nine months ended September 30, 2017 effectively increased $3.0 million, or 5.9%, and $4.4 million, or 2.9%, respectively compared to the same periods in 2016March 31, 2019 was primarily due to increases in other non-interest income, service charges on deposit accounts and interchange and debit card transactions fees partly offset by decreases in insurance commissions and fees and other charges, commissions and fees.non-interest income. The increases in other non-interest income for the three and nine months ended September 30, 2017 were primarily related to increases in gains on the sale of foreclosed and other assets, sundry and other miscellaneous income, income from customer foreign currency transactions and income from customer derivative and trading activities, among other things, partly offset by decreases in lease rental income and earnings on the cash surrender value of life insurance policies, among other things. Sundry income during the three and nine months ended September 30, 2017 included $1.2 million related to the collection of amounts charged-off by Western National Bank prior to our acquisition,

among other things. Gains on the sale of foreclosed and other assets during 2017 included the amortization of the deferred gain on our headquarters building, which we sold in December 2016. The increase in service charges on deposit accounts during the three and nine months ended September 30, 2017 were primarily due to increases in overdraft/insufficient funds charges on consumer and commercial accounts and consumer service charges partly offset by decreases in commercial service charges. The increase in interchange and debit card transactions fees during the three and nine months ended September 30, 2017 were primarily due to increases in income from debit card transactions and ATM service fees. The increases were primarily related to increased transaction volumes. The decrease in insurance commissions and fees during the three and nine months ended September 30, 2017 were related to decreases in contingent income, primarily related to a lack of growth within the portfolio and a deterioration in the loss performance of insurance policies previously placed, partly offset by increases in commission income,was primarily related to increases in benefit plan commissions, commissions on property and casualty policies, and life insurance commissions due to increased business volumes. Thevolumes and market rates partly offset by a decrease in performance related contingent payments. The increase in other charges, commissionsnon-interest income was primarily related to increases in sundry and other miscellaneous income and public finance underwriting fees partly offset by a decrease in income from customer derivative and trading activities. Sundry income during the three and nine months ended September 30, 2017 was primarily dueMarch 31, 2019 included the recovery of interest written-off prior to decreases in human resources consulting fee income2019 and income from corporate finance and capital market advisory services, among other things, partly offset by increases in wire transfer fees, and for the nine months ended September 30, 2017, an increase in loan processing fees,a settlement, among other things. The fluctuations in public finance underwriting fees income from customer derivative and trading activities during the three months

ended March 31, 2019 were primarily related to changes in business volumes. See the analysis of these categories of non-interest income included in the section captioned “Non-Interest Income” included elsewhere in this discussion.
Non-interest expense for the three and nine months ended September 30, 2017March 31, 2019 increased $6.1$4.2 million, or 4.0%, and $20.2 million, or 4.4%2.5%, compared to the same periodsperiod in 2016.2018. The increase during the three months ended September 30, 2017March 31, 2019 was primarily related to increases in salaries and wages, other non-interest expense andwages; technology, furniture and equipment expense; and employee benefits partly offset by decreases in deposit insurance and other non-interest expense. The increase during the nine months ended September 30, 2017 was primarily related to increases in salaries and wages other non-interest expense, deposit insurance expense, employee benefits and furniture and equipment expense. The increases in salaries werewas primarily due to increasesan increase in the number of employees and normal annual merit and market increases, as well as increases in stock compensationincentive and incentivestock compensation. The increasesincrease in other non-interest expense were primarily related to increases in guard services expense, sundry and other miscellaneous expense and travel/meals and entertainment, among other things. Guard services expense during the three and nine months ended September 30, 2017 was impacted by the effects of hurricane Harvey during the third quarter. The increases intechnology, furniture and equipment expense werewas primarily related to increases in software maintenance, and depreciation on furniture and equipment partly offset by a decrease in equipment rental expense, among other things. The increase in deposit insurance expense during the nine months ended September 30, 2017 was related to an increase in the assessment rate due to a new quarterly surcharge which began in the third quarter of 2016 and an increase in assets.software amortization. The increase in employee benefits during the nine months ended September 30, 2017 was primarily duerelated to increases in payroll taxes and expenses related to our 401(k) and profit sharing plans partly offset by a decrease inmedical benefits expense, expenses related to our defined benefit retirement plans.plans and expenses related to our 401(k) plan. The decrease in deposit insurance expense was mostly related to a decrease in our base assessment rate and the termination of the quarterly Deposit Insurance Fund surcharge in the fourth quarter of 2018. The decrease in other non-interest expense included decreases in donations expense, sundry and other miscellaneous expenses and professional services expense, among other things. Donations expense during 2018 was impacted by a significant contribution to our charitable foundation. Professional services expense during 2018 was impacted by a data security incident which resulted in unauthorized access to a third-party lockbox software program used by certain of our commercial lockbox customers to store digital images. The aforementioned items were partly offset by increases in advertising/promotions expense, partly related to new sponsorship arrangements, among other things. See the analysis of these categories of non-interest expense included in the section captioned “Non-Interest Expense” included elsewhere in this discussion.
Frost Insurance Agency, which is included in the Banking operating segment, had gross commission revenues of $10.9 million and $34.6$18.5 million during the three and nine months ended September 30, 2017March 31, 2019 and $11.0 million and $35.9$16.1 million during the three and nine months ended September 30, 2016.March 31, 2018. The decreases wereincrease was primarily related to decreases in contingent commissions, partly offset by increases in benefit plan commissions.commissions; commissions on property and casualty policies; and life insurance commissions due to increased business volumes and market rates partly offset by a decrease in contingent income, primarily related to lower growth within the portfolio partly offset by improvement in the loss performance of insurance policies previously placed. See the analysis of insurance commissions and fees included in the section captioned “Non-Interest Income” included elsewhere in this discussion.
Frost Wealth Advisors
Net income for the three and nine months ended September 30, 2017March 31, 2019 increased $1.6 million,$766 thousand, or 33.8% and $4.2 million, or 30.3%13.6%, compared to the same periodsperiod in 2016.2018. The increase during the three months ended September 30, 2017March 31, 2019 compared to the same period in 2018 was primarily duerelated to a $1.7 million increase in net interest income and a $1.3 million increasean increases in non-interest income (up $2.2 million) partly offset by an $873 thousand increase in income tax expense and a $500 thousand increase in non-interest expense. The increase during the nine months ended September 30, 2017 was primarily due to a $5.4 million increase in non-interest income and a $5.0 million increase in net interest income partly offset by a $3.9 million increase in non-interest expense and a $2.3 million increase in income tax expense.
Net interest income for the three and nine months ended September 30, 2017 increased $1.7 million, or 57.0%, and $5.0 million, or 64.5%, compared to the same periods in 2016. The increases were primarily due to an increase in the funds transfer price received for funds provided related to Frost Wealth Advisors' repurchase agreements and increases in the average volume of funds provided.(up $1.3 million).
Non-interest income for the three and nine months ended September 30, 2017March 31, 2019 increased $1.3$2.2 million, or 4.3%, and $5.4 million, or 6.0%6.6%, compared to the same periodsperiod in 2016.2018. The increases in non-interest income during the three and nine months ended September 30, 2017 wereincrease primarily related to increasesan increase in trust and investment management fees and other charges, commissions and fees. Trust and investment management fee income is the most significant income component for Frost Wealth Advisors. Investment fees are the most significant component of trust and investment management fees, making up approximately 83.5%83.2% of total trust and investment management fees for the first ninethree months of 2017.2019. Investment and other custodial account fees are

generally based on the market value of assets within a trust account. Volatility in the equity and bond markets impacts the market value of trust assets and the related investment fees. The increases in trust and investment management fees during the three and nine months ended September 30, 2017March 31, 2019 compared to the same periods in 2016 were2018 was primarily the result of increases in trust investment fees and increases in oil and gas fees. The increase in trust investment fees during 20172019 was due to higher average equity valuations and an increase in the number of accounts. The increase in other charges, commissionsoil and gas fees during the three and nine months ended September 30, 20172019 was primarily due to increases in income related to the sale of mutual funds.energy prices and new business, partly driven by enhancements to our service offering. See the analysis of trust and investment management fees and other charges, commissions and fees included in the section captioned “Non-Interest Income” included elsewhere in this discussion.
Non-interest expense for the three and nine months ended September 30, 2017March 31, 2019 increased $500 thousand, or 1.9%, and $3.9$1.3 million, or 5.1%4.7%, compared to the same periodsperiod in 2016.2018. The increases during the three and nine months ended September 30, 2017 wereincrease was primarily related to increases in net occupancyother non-interest expense and salaries and wages and employee benefits partly offset by decreases in other non-interest expense.wages. The increase in net occupancy expense and decreaseincreases in other non-interest expense werewas mostly related to an increase in platform/management fees related to Frost Investment Advisors and Frost Investment Services, among other things, partly offset by a changedecrease in the way we allocate occupancyprofessional service expenses, among our operating segments. Beginning in 2017, operating segments receive a direct charge for occupancy expense based upon cost centers within the segment. Such amounts are now reported as occupancy expense. Previously, these costs were included within the allocated overhead and reported as a component of other non-interest expense.things. The increasesincrease in salaries and wages during the three and nine months ended September 30, 2017 were primarily relateddue to an increasesincrease in the number of employees and normal annual merit and market increases. Theincreases, as well as increases in employee benefits expense during the threeincentive and nine months ended September 30, 2017 were primarily related to increases in payroll taxes, expenses related to our defined benefit retirement plans and medical insurance expense.stock compensation.
Non-Banks
The Non-Banks operating segment had a net loss of $1.7$2.8 million and $5.1 million for theduring three and nine months ended September 30, 2017, respectively, compared to a net loss of $925 thousand and $3.7 million forMarch 31, 2019 as well as during the same periodsperiod in 2016. The increases in net loss during the three and nine months ended September 30, 2017 were primarily due to increases2018. An increase in net interest expense due to anthree months ended March 31, 2019 was mostly offset by a decrease in non-interest expense and increase in non-interest income compared to the interest rates paid on our long-term borrowings.same period in 2018.

Income Taxes
We recognized income tax expense of $9.9 million and $35.1$14.0 million, for an effective tax rate of 9.6% and 11.8%10.7% for the three and nine months ended September 30, 2017March 31, 2019 compared to $10.9 million and $28.6$11.2 million, for an effective tax rate of 11.9% and 11.5%9.5% for the three and nine months ended September 30, 2016.March 31, 2018. The effective income tax rates differed from the U.S. statutory federal income tax raterates of 35%21% during the comparable periods2019 and 2018 primarily due to the effect of tax-exempt income from loans, securities and life insurance policies and the income tax effects associated with stock-based compensation. The decrease in income tax expense and the effective tax rate during the three months ended September 30, 2017 compared to the same period in 2016 was primarily related to the correction of an over-accrual of taxes that resulted from incorrectly classifying certain tax-exempt loans as taxable for federal income tax purposes since 2013. As a result, we recognized tax benefits totaling $3.7 million, which included $2.9 million related to the 2013 through 2016 tax years and $756 thousand related to the first and second quarters of 2017. The increase in income tax expense and the effective tax rate during the nine months ended September 30, 2017 was primarily related to an increase in total income with a higher proportion of taxable income relative to tax-exempt income, partly offset by the effect of the aforementioned tax benefits related to tax-exempt loans. Excluding the effect of the corrections related to tax-exempt loan interest, our effective tax rates would have been 13.2% and 12.7% for the three and nine months ended September 30, 2017, respectively.
Excluding the deferred tax effects related to other comprehensive income, net deferred tax assets totaled $59.9 million at September 30, 2017. This amount is based upon the current statutory federal income tax rate of 35%. There have been recent legislative proposals to reduce the statutory federal income tax rate. While there can be no assurance that a reduction will ultimately occur, any such reduction in the statutory federal income tax rate would impact the carrying value of our net deferred tax assets with a corresponding charge to income tax expense.

Average Balance Sheet
Average assets totaled $30.2$31.4 billion for the ninethree months ended September 30, 2017March 31, 2019 representing an increase of $1.7 billion,$225.0 million, or 6.1%0.7%, compared to average assets for the same period in 2016. The growth in average2018. Earning assets was primarily funded by deposit growth, an increase in average federal funds purchased and repurchase agreements and earnings retention. The increase was primarily reflected in earning assets, which increased $1.7 billion,decreased $48.0 million, or 6.6%0.2%, during the first ninethree months of 20172019 compared to the same period in 2016.2018. The increasedecrease in earning assets included an $821.8was primarily related to a $1.9 billion decrease in average interest-bearing deposits, federal funds sold and resell agreements mostly offset by a $910.6 million increase in average loans, a $648.9$558.2 million increase in average tax-exempt securities and a $384.9$373.4 million increase in average interest-bearingtaxable securities. Average premises and equipment increased $211.5 million, or 40.40%, primarily resulting from the adoption of a new accounting standard which required the recognition of our operating leases on our balance sheet (See Note 1 - Significant Accounting Policies in the accompanying Notes to Financial Statements). Average deposits decreased $317.3 million, or 1.20%, during the first three months of 2019 compared to the same period in 2018. The decrease included a $779.8 million decrease in non-interest bearing deposits partly offset by a $133.6 million decrease in average taxable securities. Average deposit growth included an $832.2 million increase in non-interest bearing deposits and a $699.7$462.5 million increase in interest-bearing deposit accounts. Average non-interest bearing deposits made up 41.7%39.0% and 40.9%41.5% of average total deposits during the first ninethree months of 20172019 and 2016,2018, respectively.
Loans
Loans were as follows as of the dates indicated:
September 30,
2017
 
Percentage
of Total
 December 31,
2016
 
Percentage
of Total
March 31,
2019
 
Percentage
of Total
 December 31,
2018
 
Percentage
of Total
Commercial and industrial$4,677,923
 36.8% $4,344,000
 36.3%$5,368,271
 37.3% $5,111,957
 36.3%
Energy:              
Production1,094,927
 8.6
 971,767
 8.1
1,278,366
 8.9
 1,309,314
 9.3
Service159,893
 1.3
 221,213
 1.8
166,649
 1.2
 168,775
 1.2
Other132,240
 1.0
 193,081
 1.7
114,058
 0.7
 124,509
 0.9
Total energy1,387,060
 10.9
 1,386,061
 11.6
1,559,073
 10.8
 1,602,598
 11.4
Commercial real estate:              
Commercial mortgages3,714,172
 29.2
 3,481,157
 29.1
4,256,999
 29.6
 4,121,966
 29.2
Construction1,082,229
 8.5
 1,043,261
 8.7
1,244,567
 8.6
 1,267,717
 9.0
Land307,701
 2.4
 311,030
 2.6
311,629
 2.2
 306,755
 2.2
Total commercial real estate5,104,102
 40.1
 4,835,448
 40.4
5,813,195
 40.4
 5,696,438
 40.4
Consumer real estate:              
Home equity loans357,542
 2.8
 345,130
 2.9
351,762
 2.4
 353,924
 2.5
Home equity lines of credit288,981
 2.3
 264,862
 2.2
337,312
 2.3
 337,168
 2.4
Other367,948
 2.9
 326,793
 2.7
438,678
 3.1
 427,898
 3.0
Total consumer real estate1,014,471
 8.0
 936,785
 7.8
1,127,752
 7.8
 1,118,990
 7.9
Total real estate6,118,573
 48.1
 5,772,233
 48.2
6,940,947
 48.2
 6,815,428
 48.3
Consumer and other522,748
 4.2
 473,098
 3.9
538,048
 3.7
 569,750
 4.0
Total loans$12,706,304
 100.0% $11,975,392
 100.0%$14,406,339
 100.0% $14,099,733
 100.0%
Loans increased $730.9$306.6 million, or 6.1%2.2%, compared to December 31, 2016.2018. The majority of our loan portfolio is comprised of commercial and industrial loans, energy loans and real estate loans. Commercial and industrial loans made up 36.8%37.3% and 36.3% of total loans at September 30, 2017March 31, 2019 and December 31, 2016,2018, respectively, while energy loans made up 10.9%10.8% and 11.6%11.4% of total loans, respectively, and real estate loans made up 48.1%48.2% and 48.2%48.3% of total loans, respectively, at those dates. Real estate loans include both commercial and consumer balances. Selected details related to our loan portfolio segments are presented below. Refer to our 20162018 Form 10-K for a more detailed discussion of our loan origination and risk management processes.
Commercial and industrial. Commercial and industrial loans increased $333.9$256.3 million, or 7.7%5.0%, during the first ninethree months of 2017.2019. Our commercial and industrial loans are a diverse group of loans to small, medium and large businesses. The purpose of these loans varies from supporting seasonal working capital needs to term financing of equipment. While some short-term loans may be made on an unsecured basis, most are secured by the assets being financed with collateral margins that are consistent with

our loan policy guidelines. The commercial and industrial loan portfolio also includes commercial leases and purchased shared national credits ("SNC"s).
Energy. Energy loans include loans to entities and individuals that are engaged in various energy-related activities including (i) the development and production of oil or natural gas, (ii) providing oil and gas field servicing, (iii) providing energy-related transportation services (iv) providing equipment to support oil and gas drilling (v) refining petrochemicals, or (vi) trading oil, gas and related commodities. Energy loans increased $999 thousand,decreased $43.5 million, or 0.1%2.7%, during the first ninethree months of 20172019 compared to December 31, 2016. The increase was related to an increase in production loans mostly offset by decreases in service and other loans.2018. The average loan size, the significance of the portfolio and the specialized nature of the energy industry requires a highly

prescriptive underwriting policy. Exceptions to this policy are rarely granted. Due to the large borrowing requirements of this customer base, the energy loan portfolio includes participations and SNCs.
Purchased Shared National Credits. Purchased shared national credits are participations purchased from upstream financial organizations and tend to be larger in size than our originated portfolio. Our purchased SNC portfolio totaled $795.4$847.6 million at September 30, 2017,March 31, 2019, increasing $23.3$90.1 million, or 3.0%11.9%, from $772.2$757.5 million at December 31, 2016.2018. At September 30, 2017, 53.4%March 31, 2019, 52.0% of outstanding purchased SNCs were related to the energy industry and 16.4% of outstanding purchased SNCs were16.2% related to the construction industry. The remaining purchased SNCs were diversified throughout various other industries, with no other single industry exceeding 10% of the total purchased SNC portfolio. Additionally, almost all of the outstanding balance of purchased SNCs was included in the energy and commercial and industrial portfolio, with the remainder included in the real estate categories. SNC participations are originated in the normal course of business to meet the needs of our customers. As a matter of policy, we generally only participate in SNCs for companies headquartered in or which have significant operations within our market areas. In addition, we must have direct access to the company’s management, an existing banking relationship or the expectation of broadening the relationship with other banking products and services within the following 12 to 24 months. SNCs are reviewed at least quarterly for credit quality and business development successes.
Commercial Real Estate. Commercial real estate loans totaled $5.1$5.8 billion at September 30, 2017,March 31, 2019, increasing $268.7$116.8 million compared to $4.8$5.7 billion at December 31, 2016.2018. At such dates, commercial real estate loans represented 83.4%83.8% and 83.8%83.6% of total real estate loans, respectively. The majority of this portfolio consists of commercial real estate mortgages, which includes both permanent and intermediate term loans. These loans are viewed primarily as cash flow loans and secondarily as loans secured by real estate. Consequently, these loans must undergo the analysis and underwriting process of a commercial and industrial loan, as well as that of a real estate loan. At September 30, 2017,March 31, 2019, approximately 51%50% of the outstanding principal balance of our commercial real estate loans were secured by owner-occupied properties.
Consumer Real Estate and Other Consumer Loans. The consumer loan portfolio, including all consumer real estate and consumer installment loans, totaled $1.5$1.7 billion at September 30, 2017both March 31, 2019 and $1.4 billion at December 31, 2016.2018. Consumer real estate loans, increased $77.7$8.8 million, or 8.3%0.8%, from December 31, 2016.2018. Combined, home equity loans and lines of credit made up 63.7%61.1% and 65.1%61.8% of the consumer real estate loan total at September 30, 2017March 31, 2019 and December 31, 2016,2018, respectively. We offer home equity loans up to 80% of the estimated value of the personal residence of the borrower, less the value of existing mortgages and home improvement loans. In general, we do not originate 1-4 family mortgage loans; however, from time to time, we may invest in such loans to meet the needs of our customers or for other regulatory compliance purposes. Consumer and other loans increased $49.7decreased $31.7 million, or 10.5%5.6%, from December 31, 2016.2018. The consumer and other loan portfolio primarily consists of automobile loans, overdrafts, unsecured revolving credit products, personal loans secured by cash and cash equivalents and other similar types of credit facilities.

Non-Performing Assets
Non-performing assets and accruing past due loans are presented in the table below. Troubled debt restructurings on non-accrual status are reported as non-accrual loans. Troubled debt restructurings on accrual status are reported separately.
September 30,
2017
 December 31,
2016
March 31,
2019
 December 31,
2018
Non-accrual loans:      
Commercial and industrial$37,239
 $31,475
$16,035
 $9,239
Energy96,717
 57,571
45,673
 46,932
Commercial real estate:      
Buildings, land and other6,773
 8,550
26,760
 15,268
Construction
 
410
 
Consumer real estate2,167
 2,130
1,860
 892
Consumer and other208
 425
1,424
 1,408
Total non-accrual loans143,104
 100,151
92,162
 73,739
Restructured loans4,815
 
4,028
 
Foreclosed assets:      
Real estate2,094
 2,440
1,175
 1,175
Other
 

 
Total foreclosed assets2,094
 2,440
1,175
 1,175
Total non-performing assets$150,013
 $102,591
$97,365
 $74,914
      
Ratio of non-performing assets to:      
Total loans and foreclosed assets1.18% 0.86%0.68% 0.53%
Total assets0.48
 0.34
0.31
 0.23
Accruing past due loans:      
30 to 89 days past due$52,044
 $55,456
$58,941
 $59,595
90 or more days past due27,121
 24,864
13,789
 20,468
Total accruing past due loans$79,165
 $80,320
$72,730
 $80,063
Ratio of accruing past due loans to total loans:      
30 to 89 days past due0.41% 0.46%0.41% 0.42%
90 or more days past due0.21
 0.21
0.10
 0.15
Total accruing past due loans0.62% 0.67%0.51% 0.57%
Non-performing assets include non-accrual loans, troubled debt restructurings and foreclosed assets. Non-performing assets at September 30, 2017March 31, 2019 increased $47.4$22.5 million from December 31, 2016 primarily due to an increase2018 reflecting increases in non-accrual energycommercial real estate loans, and, to a lesser extent, non-accrual commercial and industrial loans and restructured loans. There were no non-accrual commercial industrial loans in excess of $5.0 million at March 31, 2019 or December 31, 2018. Non-accrual energy loans included fourtwo credit relationships in excess of $5 million totaling $86.4$43.6 million at September 30, 2017. Of this amount, $29.0 million related to two credit relationships that wereMarch 31, 2019, each of which was previously reported as non-accrual at December 31, 2016 and $57.5 million related to two credit relationships that were placed on non-accrual status during the third quarterwith an aggregate balance of 2017, one of which was a $43.1 million credit relationship that was previously reported as a potential problem loan at June 30, 2017. Non-accrual energy loans included four credit relationships in excess of $5 million totaling $52.1$44.0 million at December 31, 2016. Of this amount, we charged-off a total of $10.0 million related to two credit relationships during the first and second quarters of 2017. The outstanding balance of these two credit relationships was $20.5 million at December 31, 2016. Subsequent to the charge-off, the remaining balance of one of these credit relationships was paid-off. The outstanding balance of the other credit relationship totaled $4.9 million at September 30, 2017 and is included in non-accrual energy loans in the table above. Non-accrual commercial and industrial loans included one credit relationship in excess of $5 million totaling $22.0 million at September 30, 2017. This credit relationship was placed on non-accrual status during the third quarter of 2017 and was previously classified as “substandard - accrual” (risk grade 11) at June 30, 2017, though not reported as a potential problem at that time. Non-accrual commercial and industrial loans included one credit relationship in excess of $5 million totaling $9.8 million at December 31, 2016. Of this amount, we charged-off $4.7 million during the third quarter of 2017. The outstanding balance of this credit relationship totaled $4.9 million at September 30, 2017 and is included in non-accrual commercial and industrial loans in the table above.2018. Non-accrual real estate loans primarily consist of land development, 1-4 family residential construction credit relationships and loans secured by office buildings and religious facilities. Non-accrual commercial real estate loans included two relationships in excess of $5.0 million totaling $20.2 million at March 31, 2019. Non-accrual commercial real estate loans included one relationship in excess of $5.0 million totaling $12.2 million at December 31, 2018.
Generally, loans are placed on non-accrual status if principal or interest payments become 90 days past due and/or management deems the collectibility of the principal and/or interest to be in question, as well as when required by regulatory requirements. Once interest accruals are discontinued, accrued but uncollected interest is charged to current year operations. Subsequent receipts

on non-accrual loans are recorded as a reduction of principal, and interest income is recorded only after principal recovery is reasonably assured. Classification of a loan as non-accrual does not preclude the ultimate collection of loan principal or interest.
Restructured loans totaled $4.0 million at March 31, 2019 and consisted of four notes related to a single credit relationship primarily related to commercial real estate. There were no restructured loans at December 31, 2018.
Foreclosed assets represent property acquired as the result of borrower defaults on loans. Foreclosed assets are recorded at estimated fair value, less estimated selling costs, at the time of foreclosure. Write-downs occurring at foreclosure are charged against the allowance for loan losses. Regulatory guidelines require us to reevaluate the fair value of foreclosed assets on at least an annual basis. Our policy is to comply with the regulatory guidelines. Write-downs are provided for subsequent declines in value

and are included in other non-interest expense along with other expenses related to maintaining the properties. Write-downsThere were no write-downs of foreclosed assets were not significant during the ninethree months ended September 30, 2017 or 2016.March 31, 2019 while write-downs of foreclosed assets totaled $473 thousand during the three months ended March 31, 2018.
Potential problem loans consist of loans that are performing in accordance with contractual terms but for which management has concerns about the ability of an obligor to continue to comply with repayment terms because of the obligor’s potential operating or financial difficulties. Management monitors these loans closely and reviews their performance on a regular basis. At September 30, 2017March 31, 2019 and December 31, 2016,2018, we had $89.7$46.6 million and $62.7$63.4 million in loans of this type which are not included in any one of the non-accrual, restructured or 90 days past due loan categories. At September 30, 2017,March 31, 2019, potential problem loans consisted of seveneight credit relationships. Of the total outstanding balance at September 30, 2017, 32.5%March 31, 2019, 39.9% was related to the restaurant industry, 23.6% was related to the energy industry 24.8%and 10.9% was related to the manufacturing industry and 13.9% was related to the chemicalsautomobile industry. Weakness in these organizations’ operating performance and financial condition, loan agreement breaches and borrowing base deficits for certain energy credits, among other factors, have caused us to heighten the attention given to these credits.
Allowance for Loan Losses
The allowance for loan losses is a reserve established through a provision for loan losses charged to expense, which represents management’s best estimate of inherent losses that have been incurred within the existing portfolio of loans. The allowance, in the judgment of management, is necessary to reserve for estimated loan losses and risks inherent in the loan portfolio. Our allowance for loan loss methodology, which is more fully described in our 20162018 Form 10-K, follows the accounting guidance set forth in U.S. generally accepted accounting principles and the Interagency Policy Statement on the Allowance for Loan and Lease Losses, which was jointly issued by U.S. bank regulatory agencies. The level of the allowance reflects management’s continuing evaluation of industry concentrations, specific credit risks, loan loss and recovery experience, current loan portfolio quality, present economic, political and regulatory conditions and unidentified losses inherent in the current loan portfolio. Portions of the allowance may be allocated for specific credits; however, the entire allowance is available for any credit that, in management’s judgment, should be charged off.
The table below provides, as of the dates indicated, an allocation of the allowance for loan losses by loan type; however, allocation of a portion of the allowance to one category of loans does not preclude its availability to absorb losses in other categories:
September 30,
2017
 December 31,
2016
March 31,
2019
 December 31,
2018
Commercial and industrial$48,437
 $52,915
$58,571
 $48,580
Energy51,913
 60,653
25,343
 29,052
Commercial real estate38,075
 30,213
36,455
 38,777
Consumer real estate6,875
 4,238
5,661
 6,103
Consumer and other9,003
 5,026
10,320
 9,620
Total$154,303
 $153,045
$136,350
 $132,132
The reserve allocated to commercial and industrial loans at September 30, 2017 decreased $4.5March 31, 2019 increased $10.0 million compared to December 31, 2016.2018. The decreaseincrease was primarily due to decreasesincreases in historical valuation allowances, specific valuation allowances and specificgeneral valuation allowances partly offset by increasesa decrease in macroeconomic valuation allowances and general valuation allowances. Historical valuation allowances decreasedincreased $6.1 million from $33.3$25.4 million at December 31, 20162018 to $27.2$31.4 million at September 30, 2017.March 31, 2019. The decreaseincrease was primarily related to decreasesan increase in the volume of classified loans graded as "substandard - accrual" (risk grade 11) as well as non-classified loans graded "watch" (risk grade 9) combined with increases in the historical loss allocation factors for non-classified loans graded as “watch” (risk grade 9) and “special mention” (risk grade 10) and classified commercial and industrial loans partly offset by increases in the volume of certain categories of both non-classified and classified loans.applied to these loan grades. Classified loans consist of loans having a risk grade of 11, 12 or 13. Classified commercial and industrial loans totaled $150.5$110.0 million at September 30, 2017March 31, 2019 compared to $131.9$78.9 million at December 31, 2016.2018. The weighted-average risk grade of commercial and industrial loans was 6.386.33 at September 30, 2017March 31, 2019 compared to 6.356.30 at December 31, 2016.2018. Commercial loan net charge-offs totaled $12.2$1.9 million during the first ninethree months of 20172019 compared to $8.2$7.7 million during the first ninethree months of 2016. Specific valuation allowances decreased $3.8 million from $5.4 million at December 31, 2016 to $1.7 million at September 30, 2017.2018. Charge-offs in 20172018 included $3.6$8.2 million related to two credit relationships that, as of December 31, 2016, had associated specific valuation allowances totaling $3.5 million. Charge-offs in 2017 also included $7.4 million related to two credit relationships for which we had no specific allocation as of December 31, 2016, or at the time of charge-off. Macroeconomicrelationships. Specific valuation allowances for commercial and industrial loans increased $4.7$4.1 million from $7.5$2.6 million at December 31,

2016 2018 to $12.2$6.7 million at September 30, 2017.March 31, 2019. The increase was primarilymostly related to new specific valuation allowances totaling $4.4 million on four credit relationships which had an increase in the general macroeconomic allocation (up $5.5 million) partly offset by a decrease in the environmental risk adjustment (down $980 thousand). The general macroeconomic risk allocationaggregate outstanding balance totaling $7.9 million at September 30, 2017 was partly impacted by the effect of hurricane Harvey on our Houston and Corpus Christi market areas.March 31, 2019. General valuation allowances for commercial and industrial loans increased $689$808 thousand from $6.7$10.1 million at December 31, 20162018 to $7.4$10.9 million at September 30, 2017.March 31, 2019. The increase was primarily related to increases in the allocations for highly leveraged credit relationships, large credit relationships and loans not reviewed by concurrence combined with a decrease in the adjustment for recoveries. These items wererecoveries and an increase in the allocation for highly-leveraged transactions partly offset by decreases in the allocations for large credit relationships, excessive industry concentrations and loans not reviewed by concurrence. Macroeconomic valuation allowances for commercial and industrial loans decreased $1.0 million from $10.6 million at December 31, 2018 to $9.6 million at March 31, 2019. The decrease was primarily related to a decrease in the general macroeconomic risk allocation for excessive industry concentrations.(down $1.3 million), as further discussed below, partly offset by an increase in the environmental risk adjustment (up $298 thousand).

The reserve allocated to energy loans at September 30, 2017March 31, 2019 decreased $8.7$3.7 million compared to December 31, 2016.2018. As a result, reserves allocated to energy loans as a percentage of total energy loans totaled 3.74%1.63% at September 30, 2017March 31, 2019 compared to 4.38%1.81% at December 31, 2016.2018. This decrease was primarily related to decreases in historicalall categories of valuation allowances. General valuation allowances and macroeconomic valuation allowances and partly offset by increases in specific valuation allowances and general valuation allowances. Historical valuation allowancesfor energy loans decreased $12.7$1.8 million from $34.6$6.0 million at December 31, 20162018 to $21.9$4.2 million at September 30, 2017.March 31, 2019. The decrease was primarily related to decreases in the volume of classified energy loansallocations for highly-leveraged transactions and higher risk categories of non-classified energy loansexcessive industry concentrations partly offset by increasesa decrease in the adjustment for recoveries. Macroeconomic valuation allowances related to energy loans decreased $816 thousand from $3.7 million at December 31, 2018 to $2.9 million at March 31, 2019, due to a decrease in the environmental risk adjustment (down $419 thousand), as a result of decreases in the environmental adjustment factor and the historical loss valuation allowances to which the environmental risk adjustment factor is applied, and a decrease in the general macroeconomic risk allocation (down $397 thousand), as further discussed below. Specific valuation allowances for energy loans decreased $675 thousand from $9.7 million at December 31, 2018 to $9.0 million at March 31, 2019. Specific valuation allowances at both dates were related to four credit relationships reported as non-accrual loans totaling $39.9 million at December 31, 2018 and $39.2 million at March 31, 2019. The decrease in associated specific valuation allowances was primarily related to principal reductions on certain of these credits. We had net recoveries of energy loans totaling $47 thousand during the three months ended March 31, 2019 compared to net charge-offs of $2.8 million during the same period in 2018. Historical valuation allowances decreased $404 thousand from $9.7 million at December 31, 2018 to $9.3 million at March 31, 2019. The decrease was partly related to decreases in the historical loss allocation factors for both non-classified energy loans and classified energy loans. ClassifiedThe decrease was also partly related to decreases in the volume of non-classified energy loans totaled $190.7graded as "pass"(risk grades below 9) (down $93.5 million) and "special mention" (risk grade 10) (down $7.9 million) partly offset by increases in the volume of non-classified energy loans graded as "watch" (risk grade 9) (up $46.1 million) and classified energy loans graded as "substandard - accrual" (risk grade 11) (up $13.1 million). Total classified energy loans increased $11.8 million at September 30, 2017 compared to $302.0from $72.4 million at December 31, 2016, decreasing $111.2 million. Non-classified energy loans graded as “watch” and “special mention” totaled $114.02018 to $84.2 million at September 30, 2017 compared to $229.4 million at DecemberMarch 31, 2016, decreasing $115.4 million, while "pass" grade energy loans increased $227.7 million from $854.7 million at December 31, 2016 to $1.1 billion at September 30, 2017. As a result of these changes, the2019. The weighted-average risk grade of energy loans decreasedincreased to 7.216.35 at September 30, 2017March 31, 2019 from 7.956.22 at December 31, 2016. Macroeconomic valuation allowances related to energy loans decreased $6.4 million from $18.5 million at December 31, 2016 to $12.1 million at September 30, 2017, in part due to improving trends in the weighted-average risk grade of the energy loan portfolio and decreased oil price volatility. The price per barrel of crude oil was approximately $54 at December 31, 2016 and $52 at September 30, 2017. Despite the overall decrease, macroeconomic valuation allowances related to energy loans at September 30, 2017 were partly impacted by the effect of hurricane Harvey on our Houston and Corpus Christi market areas. Specific valuation allowances for energy loans increased $9.5 million from $3.8 million at December 31, 2016 to $13.3 million at September 30, 2017. Specific valuation allowances at September 30, 2017 were related to two credit relationships totaling $61.8 million while specific valuation allowances at December 31, 2016 were related to three credit relationships totaling $29.8 million. Energy loan net charge-offs totaled $10.0 million during the first nine months of 2017 compared to net charge-offs of $18.6 million during the first nine months of 2016. The charge-offs in 2017 included $10.0 million related to two credit relationships that, as of December 31, 2016, had associated specific valuation allowances totaling $3.4 million. General valuation allowances increased $908 thousand primarily due to an increase in the allocation for excessive industry concentrations partly offset by and increase in the adjustment for recoveries.2018.
The reserve allocated to commercial real estate loans at September 30, 2017 increased $7.9March 31, 2019 decreased $2.3 million compared to December 31, 2016.2018. The increasedecrease was primarily related to increasesdecreases in macroeconomic valuation allowances and historicalgeneral valuation allowances. Macroeconomic valuation allowances increased $6.7decreased $1.8 million from $8.2$11.0 million at December 31, 20162018 to $14.9$9.2 million at September 30, 2017.March 31, 2019. The increasedecrease was primarily related to an increasea decrease in the general macroeconomic risk allocation (up $6.3(down $1.4 million), as further discussed below, and a decrease in the environmental risk adjustment (up $503(down $340 thousand). The increase, primarily resulting from a decrease in macroeconomicthe environmental risk adjustment factor. General valuation allowances reflects current economic trends impacting our Houston market area which has been impacted by decreased construction, higher rent concessions and higher vacancy rates. Macroeconomic valuation allowances were also partly impacted by the effect of hurricane Harvey on our Houston and Corpus Christi market areas. Historical valuation allowances increased $1.3 million primarily due to an increase in the volume of non-classified commercial real estate loans. Non-classifiedfor commercial real estate loans increased $267.5decreased $554 thousand from $4.4 million fromat December 31, 20162018 to September 30, 2017$3.8 million at March 31, 2019. The decrease was primarily duerelated to an increasedecreases in allocations for large credit relationships, loans not reviewed by concurrence and policy exceptions. Specific valuation allowances and historical valuation allowances related to commercial real estate loans graded as “pass.”did not significantly change during the first three months of 2019. Classified commercial real estate loans increased $1.2 million$544 thousand from $76.3$118.3 million at December 31, 20162018 to $77.5$118.8 million at September 30, 2017 due to an increase in loans classified as “substandard - accrual” (risk grade 11).March 31, 2019. The weighted-average risk grade of commercial real estate loans was 6.987.05 at September 30, 2017 compared to 6.96 atboth March 31, 2019 and December 31, 2016.2018.
The reserve allocated to consumer real estate loans at September 30, 2017 increased $2.6 millionMarch 31, 2019 decreased $442 thousand compared to December 31, 2016.2018. This increasedecrease was mostlyprimarily due to a $1.9 million increase$308 thousand decrease in macroeconomic valuation allowances, which was partly impacted by the effect of hurricane Harvey on our Houston and Corpus Christi market areas,as further discussed below, and a $534$117 thousand increasedecrease in generalhistorical valuation allowances, which was primarily related to an increase in allowances allocated for loans not reviewed by concurrence and a decreasedecreases in the reduction for recoveries.historical loss allocation factors applied to consumer real estate loans.
The reserve allocated to consumer and other loans at September 30, 2017March 31, 2019 increased $4.0 million$700 thousand compared to December 31, 2016.2018. The increase was also primarily related to increases in macroeconomic valuation allowances, historical valuation allowances and, to a lesser extent, an increase in general valuation allowances. The increase in macroeconomic valuation allowances was related to a $2.7 million increase in the general macroeconomic allocation, which was primarily related to growth in unsecured personal lines of credit, and also partly impacted by the effect of hurricane Harvey on our Houston and Corpus Christi market

areas. The$854 thousand increase in historical valuation allowances was primarily due to an increase in the volume of non-classified consumer and other loans. Thehistorical loss allocation factor. This increase was partly offset by a decrease in generalmacroeconomic valuation allowances was(down $100 thousand), primarily related to an increase in the allocation for loans not reviewed by concurrence and a decrease in the adjustmentgeneral macroeconomic risk allocation, as further discussed below.
As more fully discussed in our 2018 Form 10-K, under our allowance methodology, we allocate additional reserves for recoveries.general macroeconomic risk in excess of our minimum calculated need using our allowance model. These additional reserves are based upon management's assessment of current and expected economic conditions, trends and other quantitative and qualitative portfolio risk factors that are external to us or that are not otherwise captured in our allowance modeling process but impact the credit risk or inherent losses within our loan portfolio segments. These additional reserves are allocated to our various portfolio segments based upon management judgment.

Activity in the allowance for loan losses is presented in the following table.
Three Months Ended 
 September 30,
 Nine Months Ended 
 September 30,
Three Months Ended 
 March 31,
2017 2016 2017 20162019 2018
Balance at beginning of period$149,558
 $149,714
 $153,045
 $135,859
$132,132
 $155,364
Provision for loan losses10,980
 5,045
 27,358
 42,734
11,003
 6,945
Charge-offs:          
Commercial and industrial(5,468) (4,036) (14,574) (10,754)(2,688) (9,252)
Energy
 (884) (10,595) (18,644)
 (2,850)
Commercial real estate
 (9) (14) (56)(60) (5)
Consumer real estate(766) (287) (779) (464)(1,778) (719)
Consumer and other(4,120) (3,300) (11,291) (9,276)(5,697) (3,972)
Total charge-offs(10,354) (8,516) (37,253) (39,194)(10,223) (16,798)
Recoveries:          
Commercial and industrial903
 957
 2,419
 2,577
750
 1,577
Energy451
 19
 585
 21
47
 1
Commercial real estate268
 277
 790
 875
90
 88
Consumer real estate137
 92
 357
 442
89
 193
Consumer and other2,360
 2,185
 7,002
 6,459
2,462
 2,515
Total recoveries4,119
 3,530
 11,153
 10,374
3,438
 4,374
Net charge-offs(6,235) (4,986) (26,100) (28,820)(6,785) (12,424)
Balance at end of period$154,303
 $149,773
 $154,303
 $149,773
$136,350
 $149,885
          
Ratio of allowance for loan losses to:          
Total loans1.21% 1.29% 1.21% 1.29%0.95% 1.12%
Non-accrual loans107.83
 154.67
 107.83
 154.67
147.95
 121.71
Ratio of annualized net charge-offs to average total loans0.20
 0.17
 0.28
 0.33
0.19
 0.38
The provision for loan losses decreased $15.4increased $4.1 million, or 36.0%58.4%, during the ninethree months ended September 30, 2017March 31, 2019 compared to the same period in 2016.2018. The level of the provision for loan losses in 2016 was reflectiveduring the three months ended March 31, 2019 primarily reflects the level of a significant increase in the volume of classified energy loans,net charge-offs and specific valuation allowances taken on certainas well as the impact of an increase in classified energy loans and increasesthe overall growth in the weighted-average risk grades of our energy, commercialloan portfolio since December 31, 2018. Net charge-offs totaled $6.8 million for three months ended March 31, 2019 compared to $12.4 million for the same period in 2018. Specific valuation allowances totaled $20.0 million at March 31, 2019 compared to $16.2 million at December 31, 2018 and industrial and commercial real estate loan portfolios.$23.4 million at March 31, 2018. Classified energy, commercial and industrial and commercial real estate loans totaled $418.7$313.0 million at September 30, 2017March 31, 2019 compared to $510.1$269.6 million at December 31, 20162018 and $498.7$369.3 million at September 30, 2016. Specific valuation allowances related to energy, commercial and industrial and commercial real estate loans totaled $14.9 million at September 30, 2017 compared to $9.2 million at DecemberMarch 31, 2016 and $7.8 million at September 30, 2016.2018. The overall weighted-average risk grade of our energy, commercial and industrial and commercial real estate loan portfolios was 6.766.66 at September 30, 2017March 31, 2019 compared to 6.846.63 at December 31, 20162018 and 6.856.76 at September 30, 2016. The level of the provision for loan losses during 2017 was mostly reflective of the level of net charge-offs during during the nine months ended September 30, 2017, which totaled $26.1 million. These charge-offs were mostly related to six credit relationships, as discussed above. March 31, 2018.
The ratio of the allowance for loan losses to total loans was 1.21%0.95% at September 30, 2017March 31, 2019 compared to 1.28%0.94% at December 31, 2016.2018. Management believes the recorded amount of the allowance for loan losses is appropriate based upon management’s best estimate of probable losses that have been incurred within the existing portfolio of loans. Should any of the factors considered by management in evaluating the appropriate level of the allowance for loan losses change, our estimate of probable loan losses could also change, which could affect the level of future provisions for loan losses.

Capital and Liquidity
Capital. Shareholders’ equity totaled $3.2$3.6 billion at September 30, 2017March 31, 2019 and $3.0$3.4 billion December 31, 2016.2018. In addition to net income of $263.6$116.5 million, other sources of capital during the ninethree months ended September 30, 2017March 31, 2019 included $82.3 million of other comprehensive income, net of tax, $45.4of $157.4 million; $4.9 million in proceeds from stock option exercisesexercises; and $9.0$3.7 million related to stock-based compensation. Uses of capital during the ninethree months ended September 30, 2017March 31, 2019 included $113.8$44.6 million of dividends paid on preferred and common stock.stock and $12.6 million related to the cumulative effect of a new accounting principle adopted during the first quarter of 2019. See Note 1 - Significant Accounting Policies.
The accumulated other comprehensive income/loss component of shareholders’ equity totaled a net, after-tax, unrealized gain of $57.7$93.8 million at September 30, 2017March 31, 2019 compared to a net, after-tax, unrealized loss of $24.6$63.6 million at December 31, 2016.2018. The change was primarily due to an $85.3a $156.5 million net, after-tax, increasechange in the net unrealized gaingain/loss on securities available for sale.

Under the Basel III Capital Rules, we have elected to opt-out of the requirement to include most components of accumulated other comprehensive income in regulatory capital. Accordingly, amounts reported as accumulated other comprehensive income/loss do not increase or reduce regulatory capital and are not included in the calculation of risk-based capital and leverage ratios. Regulatory agencies for banks and bank holding companies utilize capital guidelines designed to measure capital and take into consideration the risk inherent in both on-balance sheet and off-balance sheet items. See Note 87 - Capital and Regulatory Matters in the accompanying notes to consolidated financial statements included elsewhere in this report.
We paid a quarterly dividend of $0.54, $0.57$0.67 and $0.57 per common share during the first second and third quarters of 2017, respectively,2019 and a quarterly dividend of $0.53, $0.54 and $0.54 per common share during the first, second and third quarters of 2016,2018, respectively. This equates to a common stock dividend payout ratio of 41.8%37.2% and 46.9%35.0% during the first ninethree months of 20172019 and 2016,2018, respectively. Our ability to declare or pay dividends on, or purchase, redeem or otherwise acquire, shares of our capital stock may be impacted by certain restrictions under the terms of our junior subordinated deferrable interest debentures and our Series A Preferred Stock as described in Note 87 - Capital and Regulatory Matters in the accompanying notes to consolidated financial statements included elsewhere in this report.
Stock Repurchase Plans. From time to time, our board of directors has authorized stock repurchase plans. In general, stock repurchase plans allow us to proactively manage our capital position and return excess capital to shareholders. Shares purchased under such plans also provide us with shares of common stock necessary to satisfy obligations related to stock compensation awards. On October 27, 2016,24, 2017, our board of directors authorized a $100.0$150.0 million stock repurchase program, allowing us to repurchase shares of our common stock over a two-yeartwo year period from time to time at various prices in the open market or through private transactions. DuringNo shares were repurchased under this plan during the thirdfirst quarter of 2017,2019 while we repurchased 1,134,9661,027,292 shares under the plan at a total cost of $100.0 million. On October 24, 2017, our boardmillion during the fourth quarter of directors authorized a new $150.0 million stock repurchase plan allowing us to repurchase shares of our common stock over a two-year period from time to time at various prices2018. See Note 7 - Capital and Regulatory Matters in the open market or through private transactions. Seeaccompanying notes to consolidated financial statements and Part II, Item 2 - Unregistered Sales of Equity Securities and Use of Proceeds, each included elsewhere in this report.
Liquidity. As more fully discussed in our 20162018 Form 10-K, our liquidity position is continuously monitored and adjustments are made to the balance between sources and uses of funds as deemed appropriate. Liquidity risk management is an important element in our asset/liability management process. We regularly model liquidity stress scenarios to assess potential liquidity outflows or funding problems resulting from economic disruptions, volatility in the financial markets, unexpected credit events or other significant occurrences deemed problematic by management. These scenarios are incorporated into our contingency funding plan, which provides the basis for the identification of our liquidity needs. As of September 30, 2017,March 31, 2019, management is not aware of any events that are reasonably likely to have a material adverse effect on our liquidity, capital resources or operations. In addition, management is not aware of any regulatory recommendations regarding liquidity, that would have a material adverse effect on us.
Since Cullen/Frost is a holding company and does not conduct operations, its primary sources of liquidity are dividends upstreamed from Frost Bank and borrowings from outside sources. Banking regulations may limit the amount of dividends that may be paid by Frost Bank. See Note 87 - Capital and Regulatory Matters in the accompanying notes to consolidated financial statements included elsewhere in this report regarding such dividends. At September 30, 2017,March 31, 2019, Cullen/Frost had liquid assets, including cash and resell agreements, totaling $241.3$256.7 million.
Accounting Standards Updates
See Note 1817 - Accounting Standards Updates in the accompanying notes to consolidated financial statements included elsewhere in this report for details of recently issued accounting pronouncements and their expected impact on our financial statements.


Consolidated Average Balance Sheets and Interest Income Analysis - QuarterYear To Date
(Dollars in thousands - taxable-equivalent basis)
September 30, 2017 September 30, 2016March 31, 2019 March 31, 2018
Average
Balance
 Interest
Income/
Expense
 Yield/
Cost
 Average
Balance
 Interest
Income/
Expense
 Yield/
Cost
Average
Balance
 Interest
Income/
Expense
 Yield/
Cost
 Average
Balance
 Interest
Income/
Expense
 Yield/
Cost
Assets:                      
Interest-bearing deposits$3,351,576
 $10,800
 1.28% $3,190,306
 $4,111
 0.51%$1,728,982
 $10,639
 2.50% $3,682,909
 $14,094
 1.55%
Federal funds sold and resell agreements72,239
 244
 1.34
 28,152
 48
 0.68
249,946
 1,588
 2.58
 186,278
 761
 1.66
Securities:                      
Taxable4,970,647
 23,203
 1.88
 5,391,848
 25,897
 1.97
4,540,814
 24,679
 2.19
 4,167,397
 20,558
 1.99
Tax-exempt7,360,643
 96,912
 5.34
 6,983,626
 92,917
 5.53
8,229,430
 82,475
 4.03
 7,671,186
 78,334
 4.12
Total securities12,331,290
 120,115
 3.94
 12,375,474
 118,814
 3.97
12,770,244
 107,154
 3.37
 11,838,583
 98,892
 3.36
Loans, net of unearned discounts12,587,290
 141,622
 4.46
 11,457,464
 115,674
 4.02
14,205,191
 186,650
 5.33
 13,294,638
 152,367
 4.65
Total Earning Assets and Average Rate Earned28,342,395
 272,781
 3.85
 27,051,396
 238,647
 3.57
28,954,363
 306,031
 4.27
 29,002,408
 266,114
 3.71
Cash and due from banks483,497
     487,456
    522,701
     511,948
    
Allowance for loan losses(152,237)     (152,549)    (133,647)     (156,517)    
Premises and equipment, net522,413
     564,764
    735,090
     523,576
    
Accrued interest and other assets1,194,316
     1,180,987
    1,277,795
     1,249,881
    
Total Assets$30,390,384
     $29,132,054
    $31,356,302
     $31,131,296
    
                      
Liabilities:                      
Non-interest-bearing demand deposits:                      
Commercial and individual$10,159,636
     $9,225,059
    $9,634,087
     $10,282,274
    
Correspondent banks233,748
     292,971
    205,735
     224,935
    
Public funds362,779
     484,543
    352,467
     464,850
    
Total non-interest-bearing demand deposits10,756,163
     10,002,573
    10,192,289
     10,972,059
    
Interest-bearing deposits:                      
Private accounts                      
Savings and interest checking6,344,476
 347
 0.02
 5,948,616
 264
 0.02
6,773,862
 1,472
 0.09
 6,635,495
 1,137
 0.07
Money market deposit accounts7,501,285
 4,513
 0.24
 7,473,650
 1,170
 0.06
7,695,514
 20,640
 1.09
 7,590,194
 7,698
 0.41
Time accounts766,339
 412
 0.21
 807,055
 278
 0.14
895,464
 3,156
 1.43
 778,309
 984
 0.51
Public funds381,632
 396
 0.41
 420,281
 37
 0.03
554,415
 1,906
 1.39
 452,767
 819
 0.73
Total interest-bearing deposits14,993,732
 5,668
 0.15
 14,649,602
 1,749
 0.05
15,919,255
 27,174
 0.69
 15,456,765
 10,638
 0.28
Total deposits25,749,895
     24,652,175
    26,111,544
     26,428,824
    
Federal funds purchased and repurchase agreements1,005,486
 523
 0.21
 797,417
 44
 0.02
1,180,163
 5,016
 1.72
 1,050,410
 634
 0.24
Junior subordinated deferrable interest debentures136,164
 1,020
 3.00
 136,107
 839
 2.47
136,251
 1,498
 4.40
 136,193
 1,142
 3.35
Subordinated notes payable and other notes98,498
 1,164
 4.73
 99,948
 350
 1.40
98,733
 1,164
 4.72
 98,576
 1,164
 4.72
Total Interest-Bearing Funds and Average Rate Paid16,233,880
 8,375
 0.21
 15,683,074
 2,982
 0.08
17,334,402
 34,852
 0.81
 16,741,944
 13,578
 0.33
Accrued interest and other liabilities168,572
     285,585
    388,743
     161,855
    
Total Liabilities27,158,615
     25,971,232
    27,915,434
     27,875,858
    
Shareholders’ Equity3,231,769
     3,160,822
    3,440,868
     3,255,438
    
Total Liabilities and Shareholders’ Equity$30,390,384
     $29,132,054
    $31,356,302
     $31,131,296
    
Net interest income  $264,406
     $235,665
    $271,179
     $252,536
  
Net interest spread    3.64%     3.49%    3.46%     3.38%
Net interest income to total average earning assets    3.73%     3.53%    3.79%     3.52%
For these computations: (i) average balances are presented on a daily average basis, (ii) information is shown on a taxable-equivalent basis assuming a 35%21% tax rate, (iii) average loans include loans on non-accrual status, and (iv) average securities include unrealized gains and losses on securities available for sale while yields are based on average amortized cost.




Consolidated Average Balance Sheets and Interest Income Analysis - Year To Date
(Dollars in thousands - taxable-equivalent basis)
 September 30, 2017 September 30, 2016
 Average
Balance
 Interest
Income/
Expense
 Yield/
Cost
 Average
Balance
 Interest
Income/
Expense
 Yield/
Cost
Assets:           
Interest-bearing deposits$3,341,710
 $26,712
 1.07% $2,956,822
 $11,366
 0.51%
Federal funds sold and resell agreements56,581
 514
 1.21
 34,179
 165
 0.64
Securities:           
Taxable5,112,072
 72,032
 1.90
 5,245,649
 77,402
 2.02
Tax-exempt7,309,739
 293,888
 5.39
 6,660,843
 270,586
 5.58
Total securities12,421,811
 365,920
 3.96
 11,906,492
 347,988
 4.01
Loans, net of unearned discounts12,319,125
 397,817
 4.32
 11,497,340
 344,289
 4.00
Total Earning Assets and Average Rate Earned28,139,227
 790,963
 3.77
 26,394,833
 703,808
 3.60
Cash and due from banks503,818
     504,074
    
Allowance for loan losses(152,604)     (151,643)    
Premises and equipment, net522,768
     561,215
    
Accrued interest and other assets1,211,309
     1,180,513
    
Total Assets$30,224,518
     $28,488,992
    
            
Liabilities:           
Non-interest-bearing demand deposits:           
Commercial and individual$10,054,481
     $9,055,750
    
Correspondent banks253,567
     322,495
    
Public funds417,555
     515,195
    
Total non-interest-bearing demand deposits10,725,603
     9,893,440
    
Interest-bearing deposits:           
Private accounts           
Savings and interest checking6,352,986
 892
 0.02
 5,610,695
 778
 0.02
Money market deposit accounts7,454,421
 6,929
 0.12
 7,441,626
 3,545
 0.06
Time accounts777,202
 1,040
 0.18
 813,297
 853
 0.14
Public funds433,395
 848
 0.26
 452,655
 133
 0.04
Total interest-bearing deposits15,018,004
 9,709
 0.09
 14,318,273
 5,309
 0.05
Total deposits25,743,607
     24,211,713
    
Federal funds purchased and repurchase agreements942,400
 849
 0.12
 734,022
 152
 0.03
Junior subordinated deferrable interest debentures136,150
 2,890
 2.83
 136,092
 2,392
 2.34
Subordinated notes payable and other notes87,173
 2,696
 4.12
 99,918
 958
 1.28
Total Interest-Bearing Funds and Average Rate Paid16,183,727
 16,144
 0.13
 15,288,305
 8,811
 0.08
Accrued interest and other liabilities161,643
     259,131
    
Total Liabilities27,070,973
     25,440,876
    
Shareholders’ Equity3,153,545
     3,048,116
    
Total Liabilities and Shareholders’ Equity$30,224,518
     $28,488,992
    
Net interest income  $774,819
     $694,997
  
Net interest spread    3.64%     3.52%
Net interest income to total average earning assets    3.69%     3.56%
For these computations: (i) average balances are presented on a daily average basis, (ii) information is shown on a taxable-equivalent basis assuming a 35% tax rate, (iii) average loans include loans on non-accrual status, and (iv) average securities include unrealized gains and losses on securities available for sale while yields are based on average amortized cost.



Item 3. Quantitative and Qualitative Disclosures About Market Risk
The disclosures set forth in this item are qualified by the section captioned “Forward-Looking Statements and Factors that Could Affect Future Results” included in Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations of this report and other cautionary statements set forth elsewhere in this report.
Refer to the discussion of market risks included in Item 7A. Quantitative and Qualitative Disclosures About Market Risk in the 20162018 Form 10-K. There has been no significant change in the types of market risks we face since December 31, 2016.2018.
We utilize an earnings simulation model as the primary quantitative tool in measuring the amount of interest rate risk associated with changing market rates. The model quantifies the effects of various interest rate scenarios on projected net interest income and net income over the next 12 months. The model measures the impact on net interest income relative to a flat-rate case scenario of hypothetical fluctuations in interest rates over the next 12 months. These simulations incorporate assumptions regarding balance sheet growth and mix, pricing and the repricing and maturity characteristics of the existing and projected balance sheet. The impact of interest rate derivatives, such as interest rate swaps, caps and floors, is also included in the model. Other interest rate-related risks such as prepayment, basis and option risk are also considered.
For modeling purposes, as of September 30, 2017,March 31, 2019, the model simulations projected that 100 and 200 basis point ratable increases in interest rates would result in positive variances in net interest income of 1.2%0.2% and 3.3%1.2%, respectively, relative to the flat-rate case over the next 12 months, while 100 and 125200 basis point ratable decreases in interest rates would result in a negative variances in net interest income of 5.1%2.5% and 9.9%7.3%, respectively, relative to the flat-rate case over the next 12 months. The September 30, 2017March 31, 2019 model simulations for increased interest rates were impacted by the assumption, for modeling purposes, that we will begin to pay interest on commercial demand deposits (those not already receiving an earnings credit rate) in the fourthsecond quarter of 2017,2019, as further discussed below. For modeling purposes, as of September 30, 2016,March 31, 2018, the model simulations projected that 100 and 200 basis point ratable increases in interest rates would result in positive variances in net interest income of 0.4%0.9% and 1.5%2.8%, respectively, relative to the flat-rate case over the next 12 months, while a decrease100 and 175 basis point ratable decreases in interest rates of 50 basis points would result in a negative variance in net interest income of 6.5%3.7% and 9.7%, respectively, relative to the flat-rate case over the next 12 months. The September 30, 2016March 31, 2018 model simulations for increased interest rates were impacted by the assumption, for modeling purposes, that we would begin to pay interest on commercial demand deposits (those not already receiving an earnings credit rate) in the fourthsecond quarter of 2016,2018, as further discussed below. The likelihood of a decrease in interest rates beyond 125175 basis points as of September 30, 2017 and 50 basis points as of September 30, 2016March 31, 2018 was considered to be remote given prevailing interest rate levels.
The model simulations as of September 30, 2017March 31, 2019 indicate that our balance sheet is moreless asset sensitive in comparison to our balance sheet as of September 30, 2016.March 31, 2018. The shift to a moreless asset sensitive position was primarily due to increasesa decrease in the relative proportion of interest-bearing deposits and federal funds sold to projected average interest-earning assets. FederalInterest-bearing deposits and federal funds sold are more immediately impacted by changes in interest rates in comparison to our other categories of earning assets.
Financial regulatory reform legislation entitled Additionally, our model simulations in 2019 assume that the “Dodd-Frank Wall Street Reform and Consumer Protection Act” (the “Dodd-Frank Act”) repealedfull impact of increases in the federal prohibitionfunds rate will not be reflected in the yields earned on interest-bearing deposits maintained at the payment of interest on demand deposits, thereby permitting depository institutions toFederal Reserve.
We do not currently pay interest on business transaction and other accounts beginning July 21, 2011. To date, we have not experienced anya significant additional interest costs as a result of the repeal. However, in light of recent increases in market interest rates, in late July 2017, we increased the interest rates we pay on mostportion of our interest-bearing deposit products.commercial demand deposits. If we began to pay interest on commercial demand deposits (those not already receiving an earnings credit rate), our balance sheet would likely become less asset sensitive. Because theAny interest rate that willwould ultimately be paid on these commercial demand deposits dependswould likely depend upon a variety of factors, some of which are beyond our control,control. For modeling purposes, we have assumed an aggressive pricing structure for the purposes of the model simulations discussed above with interest payments for commercial demand deposits (those not already receiving an earnings credit) beginning in the fourth quartersecond quarters of 2017.2018 and 2019, respectively, for each simulation. Should the actual interest rate paid on commercial demand deposits be less than the rate assumed in the model simulations, or should the interest rate paid for commercial demand deposits become an administered rate with less direct correlation to movements in general market interest rates, our balance sheet could be more asset sensitive than the model simulations might otherwise indicate.
As of September 30, 2017,March 31, 2019, the effects of a 200 basis point increase and a 125200 basis point decrease in interest rates on our derivative holdings would not result in a significant variance in our net interest income.
The effects of hypothetical fluctuations in interest rates on our securities classified as “trading” under ASC Topic 320, “Investments—Debt and Equity Securities,” are not significant, and, as such, separate quantitative disclosure is not presented.

Item 4. Controls and Procedures
As of the end of the period covered by this Quarterly Report on Form 10-Q, an evaluation was carried out by management, with the participation of its Chief Executive Officer and Chief Financial Officer, of the effectiveness of our disclosure controls and procedures (as defined in Rule 13a-15(e) under the Securities Exchange Act of 1934). Based upon that evaluation, the Chief Executive Officer and Chief Financial Officer concluded that the disclosure controls and procedures were effective as of the end of the period covered by this report. No change in our internal control over financial reporting (as defined in Rule 13a-15(f) under the Securities Exchange Act of 1934) occurred during the last fiscal quarter that materially affected, or is reasonably likely to materially affect, our internal control over financial reporting.

Part II. Other Information
Item 1. Legal Proceedings
We are subject to various claims and legal actions that have arisen in the course of conducting business. Management does not expect the ultimate disposition of these matters to have a material adverse impact on our financial statements.
Item 1A. Risk Factors
There has been no material change in the risk factors disclosed under Item 1A. of our 20162018 Form 10-K.
Item 2. Unregistered Sales of Equity Securities and Use of Proceeds
The following table provides information with respect to purchases we made or were made on our behalf or any “affiliated purchaser” (as defined in Rule 10b-18(a)(3) under the Securities Exchange Act of 1934), of our common stock during the three months ended September 30, 2017.March 31, 2019. Dollar amounts in thousands.
Period
Total Number of
Shares Purchased
 
Average Price
Paid Per Share
 
Total Number of
Shares Purchased
as Part of Publicly
Announced Plan
 
Maximum
Number of Shares
(or Approximate
Dollar Value)
That May Yet Be
Purchased Under
the Plan at the
End of the Period
July 1, 2017 to July 31, 2017169,342
 $91.11
 169,342
 $84,572
August 1, 2017 to August 31, 2017614,493
 88.69
 614,493
 30,070
September 1, 2017 to September 30, 2017351,131
 85.64
 351,131
 
Total1,134,966
 $88.11
 1,134,966
  
Period
Total Number of
Shares Purchased
 
Average Price
Paid Per Share
 
Total Number of
Shares Purchased
as Part of Publicly
Announced Plan
 
Maximum
Number of Shares
(or Approximate
Dollar Value)
That May Yet Be
Purchased Under
the Plan at the
End of the Period
January 1, 2019 to January 31, 2019
 $
 
 $50,000
February 1, 2019 to February 28, 2019
 
 
 50,000
March 1, 2019 to March 31, 20195,351
(1) 
97.07
 
 50,000
Total5,351
 $97.07
 
  
(1)All of these repurchases were made in connection with the vesting of certain share awards.



Item 3. Defaults Upon Senior Securities
None.
Item 4. Mine Safety Disclosures
None.
Item 5. Other Information
None.
Item 6. Exhibits
(a) Exhibits
Exhibit
Number
Description
31.1
31.2
32.1+
32.2+
101Interactive Data File - The instance document does not appear in the interactive data file because its XBRL tags are embedded within the inline XBRL document.
+This exhibit shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, or otherwise subject to the liability of that section, and shall not be deemed to be incorporated by reference into any filing under the Securities Act of 1933 or the Securities Exchange Act of 1934.

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.


      
   Cullen/Frost Bankers, Inc. 
   (Registrant) 
      
Date:October 26, 2017April 25, 2019 By:  /s/ Jerry Salinas 
    Jerry Salinas 
    Group Executive Vice President 
    and Chief Financial Officer 
    (Duly Authorized Officer, Principal Financial 
    Officer and Principal Accounting Officer) 


6055