X0306 4 2018-03-01 0 0000866609 ION GEOPHYSICAL CORP IO 0001297501 Hanson R Brian 2105 CITYWEST BOULEVARD SUITE 100 HOUSTON TX 77042-2855 1 1 0 0 President & CEO Common Stock 2018-03-01 4 A 0 7270 0.00 A 161595 D Common Stock 2018-03-01 4 F 0 7690 28.10 D 153905 D Common Stock 666 I Shares held by Spouse Restricted Stock issued pursuant to the Equity Investment Program and the ION Geophysical Corporation Second Amended and Restated 2013 Long Term Incentive Plan. The shares will vest in full on the date that is 90 days from the transaction date in Column 2. These shares were withheld upon the vesting of restricted stock shares to pay tax withholding obligations. Rebecca F. Sacco, attorney-in-fact 2018-03-02