Mayer Brown represented ION Geophysical Corporation in its formation of a joint venture with BGP, Inc., a subsidiary of China National Petroleum Corporation, one of the Chinese national oil companies, and the simultaneous sale by ION to BGP of shares of ION common stock. The value of the transactions were in excess of US$400,000,000.

The business of the joint venture, which will be called INOVA Geophysical Equipment Ltd., will be to manufacture, sell and develop land seismic equipment and to offer technology used in global oil and gas exploration. BGP transferred assets and stock, valued at over US$70 million, and paid ION US$108.5 million cash for a 51 percent stake in the venture. ION also issued 23.8 million shares of its common stock to BGP for $66.6 million cash. BGP now owns about 16.7 percent of ION's outstanding common stock, BGP and ION entered into an Investor Rights Agreement. ION used approximately $118 million of the proceeds to pay off a revolving line of credit and $35 million to pay off debt from a 2008 acquisition. ION said it also refinanced $101.0 million in long-term debt and received a new $100 million revolving line of credit from China Merchants Bank Co. Ltd.