ION GEOPHYSICAL CORP

CUSIP: 462044207 Class: COMMON STOCK

CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM's Holding History (CIK: 0001081019)

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

Q1 2019
Shares 16,272 Value ($000) $235 Avg Close — Range —
Q4 2018
Shares 16,272 Value ($000) $84 Avg Close — Range —
Q3 2018
Shares 16,272 Value ($000) $253 Avg Close — Range —
Q2 2018
Shares 16,272 Value ($000) $395 Avg Close — Range —
Q1 2016
Shares 20,147 Value ($000) $163 Avg Close — Range —