Appetite for the world's biggest equity listing this year shows the interest of a group that could swallow it more than 600 times over: stock-averse Japanese households.

While the initial public offerings of Japan Post Holdings Co. and its banking and insurance units may raise as much as ¥1.4 trillion, that's less than 0.2 percent of the money households have in cash or in the bank. The government priced stakes in the two subsidiaries at the top end of their marketed ranges, signaling heavy demand from the individuals who are earmarked to buy most of the shares.

"Never underestimate the purchasing power of Mr. and Mrs. Watanabe," Jesper Koll, chief executive officer of WisdomTree Japan K.K., said in an interview in Tokyo. "One of the goals for this privatization is that this becomes a catalyst to increase risk appetite and engender a portfolio shift from deposits into equities. Given the deposit base, it isn't going to be particularly difficult."