Kikkoman Corp., Japan's largest soy source maker, said Tuesday that its group net profit for the first half of the business year jumped 40.5 percent to 3.62 billion yen from a year earlier, largely thanks to brisk sales in the U.S.

The firm, which controls nearly 30 percent of the domestic soy source market, said group operating profits for the six months through September increased 37.6 percent to 7.98 billion yen, while group sales inched up 2.8 percent to 169.49 billion yen.

Kikkoman officials attributed the strong growth to robust soy sauce sales in the U.S., both for home and industrial uses. The firm's share of the U.S. market stood at around 50 percent last year, which it expects to expand upon this fiscal year.

Kikkoman has also reported solid growth in the European market, with sushi becoming a common sight at supermarkets, the officials added.

For the full year to next March, the firm projects a group net profit of 7.9 billion yen on sales revenues of 346 billion yen.