IBOC · International Bancshares Corp

GRANTED 4/2/2018 10 YEAR VESTING SCHEDULE 1ST YR 0%, 2ND YR 5%, 3RD YR 10%, 4TH YR 15%, 5TH YR 20%, 6TH YR 25%, 7TH YR 25%

GRANTED 3/20/2020 10 YEAR VESTING SCHEDULE 1ST YR 0%, 2ND YR 5%, 3RD YR 10%, 4TH YR 15%, 5TH YR 20%, 6TH YR 25%, 7TH YR 25%.

These stock appreciation rights (these "SARs") became vested and payable as of July 14, 2025. In accordance with the rules for filing a Form 4, the settlement of cash-settled SARs is treated as the simultaneous purchase of the number of shares of common stock the SARs represent and the sale of the same number of shares of common stock. Upon vesting, the SARs were only payable in cash and the reporting person did not receive any shares of the common stock, par value $1.00 per share (the "Common Stock"), of International Bancshares Corporation (the "Company").

These stock appreciation rights (these "SARs") became vested and payable as of July 14, 2025. In accordance with the rules for filing a Form 4, the settlement of cash-settled SARs is treated as the simultaneous purchase of the number of shares of common stock the SARs represent and the sale of the same number of shares of common stock. Upon vesting, the SARs were only payable in cash and the reporting person did not receive any shares of the common stock, par value $1.00 per share (the "Common Stock"), of International Bancshares Corporation (the "Company").

Represents the closing price of the Company's Common Stock on September 5, 2025, the date the SARs were exercised (the "Exercise Date").

These SARs represent the right to receive, upon exercise, a cash amount equal to the number of shares of the Company's Common Stock underlying the SARs being exercised multiplied by the excess of the fair market value of one share of Common Stock on (i) the Exercise Date, and (ii) July 14, 2022, the date the SARs were granted (the "Grant Date").

These SARs are subject to a seven-year vesting schedule and become exercisable in six percentage installments, vesting 5% on the second anniversary of the Grant Date, and 10%, 15%, 20%, 25%, and 25% on each respective anniversary of the Grant Date thereafter.

This transaction was executed in multiple trades at prices ranging from $67.73 to $69.09. The price reported above reflects the weighted average sale price. Upon request, the reporting person hereby undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

This transaction was executed in multiple trades at prices ranging from $69.19 to $70.35. The price reported above reflects the weighted average sale price. Upon request, the reporting person hereby undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

GRANTED 4/2/2018 10 YEAR VESTING SCHEDULE 1ST YR 0%, 2ND YR 5%, 3RD YR 10%, 4TH YR 15%, 5TH YR 20%, 6TH YR 25%, 7TH YR 25%

GRANTED 3/20/2020 10 YEAR VESTING SCHEDULE 1ST YR 0%, 2ND YR 5%, 3RD YR 10%, 4TH YR 15%, 5TH YR 20%, 6TH YR 25%, 7TH YR 25%.

This transaction involved the reporting person's gift of an aggregate of 9,000 shares of IBOC common stock to nine irrevocable trusts established for the reporting person's grandchildren, of which he is the trustee, with 1,000 shares being transferred to each trust. The reporting person disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interest therein.

This transaction involved the reporting person's gift of an aggregate of 9,000 shares of IBOC common stock to nine irrevocable trusts established for the reporting person's grandchildren, of which he is the trustee, with 1,000 shares being transferred to each trust. The reporting person disclaims beneficial ownership of the reported securities except to the extent of his pecuniary interest therein.

This transaction was executed in multiple trades at prices ranging from $71.00 to $72.55, inclusive. The price reported above reflects the weighted average sale price. Upon request, the reporting person hereby undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each separate price within the price range at which the transaction was effected.

These shares were held by 3NIX Ventures Ltd., a limited partnership, for which Nixco, L.C., a limited liability company, serves as the general partner, of which the reporting person is the sole manager

This transaction was executed in multiple trades at prices ranging from $72.00 to $73.16, inclusive. The price reported above reflects the weighted average sale price. Upon request, the reporting person hereby undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares sold at each seperate price within the price range at which the transaction was effected.

These shares were held by 3NIX Ventures Ltd., a limited partnership, for which Nixco, L.C., a limited liability company, serves as the general partner, of which the reporting person is the sole manager

GRANTED 4/2/2018 10 YEAR VESTING SCHEDULE 1ST YR 0%, 2ND YR 5%, 3RD YR 10%, 4TH YR 15%, 5TH YR 20%, 6TH YR 25%, 7TH YR 25%

This transaction was executed in multiple trades at prices ranging from $58.07 to $59.70. The price reported above reflects the weighted average sale price. Upon request, the reporting person hereby undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

This transaction was executed in multiple trades at prices ranging from $59.70 to $59.90. The price reported above reflects the weighted average sale price. Upon request, the reporting person hereby undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

This transaction was executed in multiple trades at prices ranging from $53.80 to $54.52. The price reported above reflects the weighted average sale price. Upon request, the reporting person hereby undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

GRANTED 2/19/14 10 YEAR VESTING SCHEDULE 1ST YR 0%, 2ND YR 5%, 3RD YR 10%, 4TH YR 15%, 5TH YR 20%, 6TH YR 25%, 7TH YR 25%

This transaction was executed in multiple trades at prices ranging from $48.50 to $49.50. The price reported above reflects the weighted average sale price. Upon request, the reporting person hereby undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

This transaction was executed in multiple trades at prices ranging from $48.50 to $49.50. The price reported above reflects the weighted average sale price. Upon request, the reporting person hereby undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

This transaction was executed in multiple trades at prices ranging from $48.50 to $49.50. The price reported above reflects the weighted average sale price. Upon request, the reporting person hereby undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

This transaction was executed in multiple trades at prices ranging from $48.50 to $49.50. The price reported above reflects the weighted average sale price. Upon request, the reporting person hereby undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

This transaction was executed in multiple trades at prices ranging from $44.25 to $44.94. The price reported above reflects the weighted average sale price. Upon request, the reporting person hereby undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

This transaction was executed in multiple trades at prices ranging from $44.67 to $45.26. The price reported above reflects the weighted average sale price. Upon request, the reporting person hereby undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

This transaction was executed in multiple trades at prices ranging from $46.28 to $47.25. The price reported above reflects the weighted average sale price. Upon request, the reporting person hereby undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

This transaction was executed in multiple trades at prices ranging from $46.95 to $48.17. The price reported above reflects the weighted average sale price. Upon request, the reporting person hereby undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

On October 4, 2023, a trust for which the reporting person serves as co-trustee distributed 10,000 shares to a beneficiary of the trust.

The reporting person disclaims beneficial ownership of the reported securities except to the extent of the pecuniary interest therein, if any.

GRANTED 3/20/2020 10 YEAR VESTING SCHEDULE 1ST YR 0%, 2ND YR 5%, 3RD YR 10%, 4TH YR 15%, 5TH YR 20%, 6TH YR 25%, 7TH YR 25%

GRANTED 4/2/2018 10 YEAR VESTING SCHEDULE 1ST YR 0%, 2ND YR 5%, 3RD YR 10%, 4TH YR 15%, 5TH YR 20%, 6TH YR 25%, 7TH YR 25%

On March 15, 2023, a trust for which the reporting person serves as co-trustee distributied 50,000 shares to a beneficiary of the trust.

The reporting person disclaims beneficial ownership of the securities except to the extent of the pecuniary interest therein, if any.

The reporting person previously adopted a dividend reinvestment plan effective March 11, 2015, which plan was terminated April 2023.

BONA FIDE GIFT

This transaction was executed in multiple trades at prices ranging from $51.60 to $52.05. The price reported above reflects the weighted average sale price. Upon request, the reporting person hereby undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

This transaction was executed in multiple trades at prices ranging from $51.99 to $52.23. The price reported above reflects the weighted average sale price. Upon request, the reporting person hereby undertakes to provide to the SEC staff, the issuer, or a security holder of the issuer, full information regarding the number of shares and prices at which the transaction was effected.

BONA FIDE GIFT

On October 5, 2022, a trust for which the reporting person serves as co-trustee distributed 100,000 shares to a beneficiary of the trust.

The reporting person disclaims beneficial ownership of the securities except to the extent of the pecuniary interest therein, if any.

BONA FIDE GIFT

BONA FIDE GIFT

The reporting person previously adopted a dividend reinvestment plan effective March 11, 2015, which plan was terminated April 2023.

GRANTED 3/20/2020 10 YEAR VESTING SCHEDULE 1ST YR 0%, 2ND YR 5%, 3RD YR 10%, 4TH YR 15%, 5TH YR 20%, 6TH YR 25%, 7TH YR 25%.