(REUTERS) - Jon Corzine, the former chief executive officer of MF Global, apologized to a U.S. House panel on Thursday for the collapse of the brokerage and said he was stunned when he first learned customer funds were missing.

I simply do not know where the money is, or why the accounts have not been reconciled to date, said Corzine in lengthy prepared remarks before the House Agriculture Committee.

I sincerely apologize, both personally and on behalf of the company, to our customers, our employees and our investors, who are bearing the brunt of the impact of the firm's bankruptcy.

Corzine also disputed claims that the now-bankrupt futures brokerage took on too much leverage and said that his involvement in the firm's clearing, settlement and payment mechanisms and accounting was limited.

(Reporting by Sarah N. Lynch in Washington; Editing by Lisa Von Ahn)