X0306 4 2018-03-01 0 0000866609 ION GEOPHYSICAL CORP IO 0001481492 Usher Christopher Theron 2105 CITYWEST BOULEVARD SUITE 100 HOUSTON TX 77042-2855 0 1 0 0 EVP & COO, OPER OPTIMIZATION Common Stock 2018-03-01 4 A 0 6605 0.00 A 58822 D Common Stock 2018-03-01 4 F 0 2042 28.10 D 56780 D 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