Shares in Nomura Holdings have fallen 16% in Tokyo following the announcement of a share issue to raise up to 510bn yen ($5.6bn; £3.5bn). The issue by Japan’s biggest brokerage is designed to help meet the expected tougher new capital requirements.

Nomura also said it would use the money to strengthen its businesses in the US and Asia. The share placing would be Nomura’s second in six months and about double the size of the first one.

“By raising this much capital now, they won’t have to worry about meeting new global capital regulations, and on top of that they will still be able to expand their business,” said Azuma Ohno, an analyst at Credit Suisse in Tokyo.

But the announcement of the sale, which could dilute existing shares by up to 30%, led to a rush of sell orders, which created such an imbalance that it was impossible to trade the shares during the morning session in Tokyo.