[ by Howard Haykin ] Dai-ichi Life, Japan's largest listed life insurer, reached an agreement to acquire a stake of up to 20% in the Janus Capital Group, a major U.S. asset manager.   Once again, a Japanese financial company has countered slowing domestic growth by expanding overseas.  The announcement caused an pre-opening 18% jump in the price of Janus shares. Benefit to Janus. This fabled stock fund manager of the 1990s has lost some of its shine after being involved in an industry wide mutual fund trading scandal and after suffering outflows from its funds over the past several years.  As of 6/30/12, Janus had  $152 billion in assets under management. Acquisition Through Exercise of Options. Based on Thursday's closing market price of Janus shares, a 20% stake in the firm would costs about $300 million.  Dai-Ichi will acquire the stake in Denver-based Janus within a year, and would range in excess of 15% but be no more than 20%.  Dai-Ichi will acquire the interest by exercising stock options. Janus has sold to Dai-ichi conditional options for the Japanese company to buy up to 14 million shares of Janus.  The U.S. mutual fund firm, in turn, will buy back its shares to offset the share dilution from that transaction. Terms of the agreement were not disclosed.  However, it's understood, Dai-ichi will take one board seat at Janus once it holds a 15% stake, and will place $2 billion of its clients' assets under Janus' management.  The Japanese insurer will further sell Janus's products in Japan through DIAM Asset Management, a joint venture between Dai-ichi and Mizuho Financial Group. For further details, go to:   [Reuters, 8/10/12].