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ION GEOPHYSICAL CORP
ION GEOPHYSICAL CORP. Institutional holdings reported to the SEC.

Institutional Holders (2015Q1)
Portfolio Summary: 140 Institutional holders with a total value of $218,404,664.
#
Manager Name
Shares
Value ($)
%
Options
Notes
1 Invesco Ltd. 32,006,561 69,454,000 31.80%
2 VANGUARD GROUP INC 9,113,771 19,777,000 9.06%
3 BlackRock Fund Advisors 7,939,693 17,229,000 7.89%
4 WELLS FARGO & COMPANY/MN 5,370,292 11,654,000 5.34%
5 DIMENSIONAL FUND ADVISORS LP 4,728,434 10,261,000 4.70%
6 BlackRock Institutional Trust Company, N.A. 3,741,327 8,119,000 3.72%
7 Neuberger Berman Group LLC 2,955,090 6,413,000 2.94%
8 STATE STREET CORP 2,511,617 5,451,000 2.50%
9 NORGES BANK 2,190,362 4,753,000 2.18%
10 PUTNAM INVESTMENTS LLC 1,827,625 3,966,000 1.82%
11 CHARLES SCHWAB INVESTMENT MANAGEMENT INC 1,783,590 3,871,000 1.77%
12 JPMORGAN CHASE & CO 1,768,021 3,837,000 1.76%
13 NORTHERN TRUST CORP 1,586,667 3,442,000 1.58%
14 Bank of New York Mellon Corp 1,525,341 3,311,000 1.52%
15 PANAGORA ASSET MANAGEMENT INC 1,478,697 3,209,000 1.47%
16 RENAISSANCE TECHNOLOGIES LLC 1,257,400 2,729,000 1.25%
17 FIRST TRUST ADVISORS LP 1,202,479 2,609,000 1.19%
18 ROYCE & ASSOCIATES LP 1,078,200 2,340,000 1.07%
19 TIAA CREF INVESTMENT MANAGEMENT LLC 950,765 2,063,000 0.94%
20 OXFORD ASSET MANAGEMENT LLP 840,106 1,823,000 0.83%
21 PRINCIPAL FINANCIAL GROUP INC 831,489 1,805,000 0.83%
22 GEODE CAPITAL MANAGEMENT, LLC 737,499 1,600,000 0.73%
23 CALIFORNIA PUBLIC EMPLOYEES RETIREMENT SYSTEM 558,300 1,368,000 0.63%
24 AMERIPRISE FINANCIAL INC 593,193 1,287,000 0.59%
25 Counsel Portfolio Services Inc. 577,175 1,252,000 0.57%
26 DEUTSCHE BANK AG\ 574,877 1,246,000 0.57%
27 GUGGENHEIM CAPITAL LLC 534,876 1,161,000 0.53%
28 PARAMETRIC PORTFOLIO ASSOCIATES LLC 510,728 1,108,000 0.51%
29 BlackRock Investment Management, LLC 469,875 1,020,000 0.47%
30 NEW YORK STATE TEACHERS RETIREMENT SYSTEM 415,082 901,000 0.41%
31 SUSQUEHANNA INTERNATIONAL GROUP, LLP 393,748 854,000 0.39%
32 GOLDMAN SACHS GROUP INC 328,823 713,000 0.33%
33 State of New Jersey Common Pension Fund D 310,000 673,000 0.31%
34 BRIDGEWAY CAPITAL MANAGEMENT, LLC 290,000 629,000 0.29%
35 DEERE & CO 287,031 623,000 0.29%
36 PRUDENTIAL FINANCIAL INC 283,904 616,000 0.28%
37 Nationwide Fund Advisors 280,875 609,000 0.28%
38 TEACHERS ADVISORS, LLC 271,079 588,000 0.27%
39 MENTA CAPITAL LLC 257,888 560,000 0.26%
40 NEW YORK STATE COMMON RETIREMENT FUND 255,965 555,000 0.25%
41 AQR CAPITAL MANAGEMENT LLC 245,650 533,000 0.24%
42 PUBLIC SECTOR PENSION INVESTMENT BOARD 241,667 524,000 0.24%
43 CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM 234,890 510,000 0.23%
44 LUCUS ADVISORS LLC 226,561 492,000 0.23%
45 RHUMBLINE ADVISERS 205,631 446,000 0.20%
46 STRS OHIO 205,200 445,000 0.20%
47 ALLIANCEBERNSTEIN L.P. 198,600 431,000 0.20%
48 WELLINGTON MANAGEMENT GROUP LLP 198,356 430,000 0.20%
49 MORGAN STANLEY 192,164 417,000 0.19%
50 BlackRock Group LTD 170,324 370,000 0.17%
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From 2023-01-03 onward, the SEC requires values to be reported in nearest dollars. Earlier filings reported values in thousands; therefore, positions shown as $0 in older filings may represent actual values between $0–$999.