SC 13G/A 1 gw13gio.txt GW CAPITAL IO 13GA Item 1 (a). Ion Geophysical Item 1 (b). 2105 CityWest BLVD, Suite 400 Houston, TX 77042-2839 Item 2 (a). GW Capital, Inc. Item 2 (b). 10900 NE 8th St., Suite 1010 Bellevue, WA 98004 Item 2 (c). Not Applicable Item 2 (d). Common Stock Item 2 (e). 462044108 Item 3 Investment Advisor registered under Section 203 of the Investment Advisors Act of 1940 Item 4 (a). 3,695,601 Item 4 (b). 3.1% Item 4 (c). (i) 2,743,447 (ii) 0 (iii) 3,695,601 (iv) 0 Item 5 No longer a beneficial owner Item 6 Not Applicable Item 7 Not Applicable Item 8 Not Applicable Item 9 Not Applicable Item 10 Not Applicable After reasonable inquiry and to the best of my know- Ledge and belief, I certify that the information set Forth in the statement is true, complete and correct. August 7, 2009 Guy Watanabe Guy Watanabe President