Nomura Holdings Inc., hit hard by the plunge in U.S. mortgage investments, reported Thursday its first loss in more than four years, forcing the company to close some operations, cut staff and shut its Chicago office.

The net loss was ¥10.5 billion, or ¥5.51 per share, for the three months that ended Sept. 30, compared with a ¥43.5 billion profit last year, Nomura said. Revenue slid to ¥464.5 billion from ¥469.2 billion.

Nomura's U.S. arm posted a $620 million loss, prompting Chief Executive Officer Nobuyuki Koga to shut the unit's residential mortgage operation, hampering efforts to increase international earnings. Merrill Lynch & Co. on Wednesday reported the biggest loss in its 93-year history after writing down $8.4 billion of subprime mortgages and leveraged debt.

"Nomura lost one wing," said Nobutomo Watanabe, deputy general manager of the financial economic department at Norinchukin Research Institute Co. "They've been trying to expand in the U.S. because the home market doesn't generate a lot of brokerage fees."

The world's biggest financial companies have reported credit and market losses of more than $30 billion after defaults on subprime U.S. mortgages contaminated securities backed by home loans and other types of debt.