TOKYO: Japan's Dai-ichi Mutual Life Insurance Co. is expected to have a market valuation of 15.5 billion dollars after its April 1 initial public offering, the world's biggest since Visa's in 2008. Japan's second-biggest life insurer will be listed at the start of next month as it will be demutualised to become a joint stock company. The company on Tuesday set the offering price at 140,000 yen (1,550 dollars) for each of the 10 million shares, for a total of 1.4 trillion yen. Of these about 7.2 million shares will be released to retail investors -- 4.6 million in Japan and 2.5 million abroad -- totalling about one trillion yen, and the remainder alloted to existing Dai-ichi policy-holders. Mizuho Financial Group Inc. would acquire a 5.6 percent stake in Dai-ichi, Sompo Japan Insurance Inc. 4.0 percent and the Bank of Tokyo-Mitsubishi UFJ 2.2 percent, Kyodo News reported earlier. Dai-ichi's IPO is set to be the world's largest since Visa's 19.7-billion-dollar offering in March 2008. It will be Japan's biggest since Nippon Telephone and Telegraph released shares in its mobile phone operator NTT DoCoMo in 1998, which came to 2.1 trillion yen. Dai-ichi Mutual has decided to list the company, which is currently a mutual corporation, so that it will be able to secure funds for investment in domestic and overseas operations. Mizuho Securities, Merrill Lynch Japan and Nomura Securities are the lead underwriters for the IPO in Japan. The joint lead managers overseas are Merrill Lynch International, Mizuho International, Nomura International and Goldman Sachs International, said Dow Jones Newswires.