The U.S. Securities and Exchange Commission said it obtained an emergency court order to freeze the assets of traders using Hong Kong and Singapore accounts to reap more than $13 million in illegal profits by trading in advance of the announcement that Cnooc Ltd. agreed to acquire Nexen Inc. (NXY)

Hong Kong-based firm Well Advantage Ltd. and other unknown traders stockpiled shares of Nexen stock based on confidential information about the deal, the SEC claimed in an e-mailed statement.

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