TOKYO (Reuters) -Japanese trading house Mitsui&Co will make a secondary share offering in overseas markets, the company said on Monday.

Mitsui Sumitomo Insurance Company Ltd and Sumitomo Mitsui Banking Corporation will be offering 11,725,000 ordinary shares and 3,208,400 ordinary shares, respectively, or a total of 14,933,400 shares, Mitsui said.

Based on the number of shares outstanding as of March 31, which include treasury stock, the offering represents nearly 1% of Mitsui shares worth around $700 million, based on the company's current market capitalisation.

Mitsui is currently conducting a share buyback, ending in September. The company did not immediately reply to a Reuters request for comment.

The offer price will be determined between June 24 and June 25. Shares are to be offered mainly in Europe and Asia, excluding the United States and Canada, Mitsui said.

(Reporting by Katya Golubkova, additional reporting by Makiko Yamazaki; Editing by Kim Coghill and Janane Venkatraman)