Sec Form 4 Filing - Usher Christopher Theron @ ION GEOPHYSICAL CORP - 2021-04-19

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Usher Christopher Theron 2. Issuer Name and Ticker or Trading Symbol ION GEOPHYSICAL CORP [ IO] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) President & CEO (Last) (First) (Middle) 2105 CITYWEST BOULEVARD, SUITE 100 3. Date of Earliest Transaction (MM/DD/YY) 04/19/2021 (Street) HOUSTON, TX77042-2855 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 04/19/2021 F 17,052 ( 1 ) D $ 2.16 258,992 D Common Stock 04/19/2021 F 6,279 ( 1 ) D $ 2.16 252,713 D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Rights Offering (Rights to Buy) ( 2 ) $ 2.78 04/20/2021 M 720 03/23/2021 04/12/2021 Common Stock 666 $ 0 0 D 8% Convertible Notes due 2025 $ 3 04/20/2021 P 04/20/2021 12/15/2025 Common Stock 666 $ 2,000 $ 2,000 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Usher Christopher Theron 2105 CITYWEST BOULEVARD SUITE 100 HOUSTON, TX77042-2855 X President & CEO Signatures /s/ Rebecca F. Sacco, attorney-in-fact 04/21/2021 Signature of Reporting Person Date

Explanation of Responses:

( 1 )These shares were not sold, but were withheld by ION Geophysical Corporation ("ION") upon the vesting of restricted stock shares to satisfy tax withholding obligations. ( 2 )These were subscription rights acquired in the ION's Rights Offering which commenced on March 23, 2021, which rights the reporting person exercised to purchase a principal amount of ION's 8.00% Senior Secured Second Priority Convertible Notes due 2025. ION issued one non-transferable subscription right for each share of Common Stock held on the March 22, 2021 record date and each subscription entitled the holder to purchase $2.78 principal amount of ION's Notes. ( 3 )These are ION's 8.00% Senior Secured Second Priority Convertible Notes due 2025 that were directly acquired by the reporting person as a result of his exercise of subscription rights which were issued to him in ION's Rights Offering.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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