The Securities and Exchange Commission said Friday that it froze assets of Hong Kong traders who bought stock in a Canadian company before a firm owned by the Chinese government announced plans to buy it this week.

The SEC said Friday that Well Advantage Limited and other traders used accounts in Hong Kong and Singapore to make over $13 million trading shares in Canadian oil and gas company Nexen Inc. based on inside information.

China’s CNOOC Ltd. Oil company announced plans to buy Nexen on Monday for $15.1 billion.

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