"Defendants effectively operated in a tag-team fashion--rotating in the roles of prime broker, clearing agent or counterparty that enabled the short sale transaction to go forward without the expectation of delivery, " the complaint says.

FORBES: Naked Shorts

The auction agent ranks the offers by their rate, and then applies to all accepted bids the clearing rate, the lowest rate at which bids will cover all the securities for sale.

FORBES: Cash Equivalents Don't Act Like Cash When It Counts

The US has approved the sale of Canadian oil firm Nexen to China's state-owned CNOOC, clearing the way for the deal to be completed.

BBC: CNOOC takeover of Nexen approved by US regulator