An executive of a financial exchange monitoring MF Global told senators Tuesday that Jon Corzine, the former head of the financial firm, knew that loans were improperly made with customer funds. The claim was made just minutes after Corzine professed his ignorance for how up to $1.2 billion in customer funds had gone missing. Terrence Duffy, the executive chairman of CME Group, the exchange that regulates MF Global, told the Senate Agriculture Committee that a CME auditor was told by an MF Global executive that Corzine knew that a loan was made to a European affiliate of the company, and...