ION GEOPHYSICAL CORP

CUSIP: 462044207 Class: COMMON STOCK

DIMENSIONAL FUND ADVISORS LP's Holding History (CIK: 0000354204)

Note: Option positions (PUT/CALL) are excluded.

Q2 2021
Shares 12,587 Value ($000) $26 Avg Close — Range —
Q1 2021
Shares 12,587 Value ($000) $27 Avg Close — Range —
Q3 2020
Shares 167,658 Value ($000) $251 Avg Close — Range —
Q2 2020
Shares 361,373 Value ($000) $846 Avg Close — Range —
Q1 2020
Shares 501,879 Value ($000) $637 Avg Close — Range —
Q4 2019
Shares 521,271 Value ($000) $4,525 Avg Close — Range —
Q3 2019
Shares 531,629 Value ($000) $4,848 Avg Close — Range —
Q2 2019
Shares 528,376 Value ($000) $4,253 Avg Close — Range —
Q1 2019
Shares 469,325 Value ($000) $6,777 Avg Close — Range —
Q4 2018
Shares 437,336 Value ($000) $2,266 Avg Close — Range —
Q3 2018
Shares 429,367 Value ($000) $6,677 Avg Close — Range —
Q2 2018
Shares 426,584 Value ($000) $10,366 Avg Close — Range —
Q1 2018
Shares 372,163 Value ($000) $10,086 Avg Close — Range —
Q4 2017
Shares 243,307 Value ($000) $4,805 Avg Close — Range —
Q3 2017
Shares 243,307 Value ($000) $2,314 Avg Close — Range —
Q2 2017
Shares 265,378 Value ($000) $1,154 Avg Close — Range —
Q1 2017
Shares 265,378 Value ($000) $1,287 Avg Close — Range —
Q4 2016
Shares 267,254 Value ($000) $1,604 Avg Close — Range —
Q3 2016
Shares 265,746 Value ($000) $1,820 Avg Close — Range —
Q2 2016
Shares 269,317 Value ($000) $1,678 Avg Close — Range —
Q1 2016
Shares 272,091 Value ($000) $2,198 Avg Close — Range —