ION GEOPHYSICAL CORP

CUSIP: 462044108 Class: COM

PUBLIC EMPLOYEES RETIREMENT ASSOCIATION OF COLORADO's Holding History (CIK: 0000315297)

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

Q1 2015
Shares 43,800 Value ($000) $95 Avg Close — Range —
Q4 2014
Shares 43,800 Value ($000) $120 Avg Close — Range —
Q3 2014
Shares 43,800 Value ($000) $122 Avg Close — Range —
Q2 2014
Shares 43,800 Value ($000) $185 Avg Close — Range —
Q1 2014
Shares 43,800 Value ($000) $184 Avg Close — Range —
Q4 2013
Shares 43,800 Value ($000) $145 Avg Close — Range —
Q3 2013
Shares 43,800 Value ($000) $228 Avg Close — Range —
Q2 2013
Shares 43,800 Value ($000) $264 Avg Close — Range —