Nomura posted a sharp gain in profits, as Japan's stock market rally gave a much-needed lift to the country's largest securities house still squeezing bloated costs and recovering from an insider trading scandal.

The firm reported a net profit of ¥82.4bn in the January-March period, its best quarterly figure in seven years. That compares with a ¥20.1bn net profit in the October-December quarter. In the same period a year earlier, Nomura posted a ¥22.1bn net profit.