Regulation of corporate groups was first properly introduced into Japan with the 2014 amendments to the Companies Act. The new rules regulate the formation of corporate groups through changes in corporate control with methods such as new share issuances (article 206-2 etc), multiple derivative actions (article 847-3 etc), and cash-outs of minorities by special controlling shareholders (articles 179 et seq.). These rules are aimed at protecting the economically privileged parent companies or their shareholders, not the weaker minority shareholders of subsidiaries or creditors. Is the regulation of corporate groups now complete with the above measures, or does Japan need further legislative intervention in this field? This paper aims to highlight the issues of Japan’s law on corporate groups going forward. Representative structures adopted by corporate groups in Japan are 1) cross-shareholdings, 2) corporate groups in the narrow sense, and 3) parent-subsidiary groups (or Konzern in the German sense). Moving from 1) to 3), the organizational aspect increases. Cross-shareholdings typically involve two companies with related businesses holding the shares of each other. In 1982 the percentage of shares held by legal persons reached a high of 72 percent. However, since 2000, listed companies in Japan have moved to unwind their cross-shareholding arrangements. Nevertheless, it is expected that cross-shareholdings will continue to serve a certain purpose in the Japanese economy insofar as it is an option for business collaboration between operating companies. Due to the inherent conflicts of nature in cross-shareholding arrangements and resistance to complete dissolution of cross-shareholding, ideal corporate governance arrangements will never be achieved with a laissez-faire approach. Currently, regulation of cross-shareholdings entails depriving a company B that is held 25% or more of its shares of another company A of all its voting rights in A (article 308(1) proviso). However, this wholesale deprivation of voting rights is problematic from a constitutional perspective, as it goes against the constitutional protection of property rights (article 29(1), Constitution of Japan). To improve corporate governance in stock companies and to expand the scope of cross-shareholding regulation, I propose that shareholdings of less than 25% should also be regulated, but only to the effect of removing voting rights only for director elections at general meeting. Corporate groups in the narrow sense include groups of companies centered on the old Zaibatsu groups such as Mitsui, Mitsubishi and Sumitomo, and banking-type groups comprising operating companies centered on a financing bank. The distinctive organizational characteristics of corporate groups are a matrix-like web of cross-shareholdings and a ‘company presidents’ club’ where representatives of companies in the group can exchange ideas and information informally. At the end of the war, Mitsui, Mitsubishi and Sumitomo’s corporate groups together accounted for approximately 22% of the entire registered capital of Japan’s companies, and the ten Zaibatsus including the Yasuda group comprised 35% - which meant that over a third of corporate capital in Japan was held by Zaibatsus. However, the six major corporate groups in modern Japan only accounted for 13.15% of corporate capital in 1999. Given the circumstances, it is unnecessary to introduce restrictions on circular cross-shareholding arrangements or joint liability for companies acting in concert through means such as company presidents’ clubs. A distinctive feature of Japanese parent-subsidiary groups is the ‘bottom-up’ decision-making structure that reserves to the subsidiary great freedom of action in operations so as to capitalize on the subsidiary’s on-the-spot knowledge. This division of powers is a major advantage of Japanese parent-subsidiary groups when adapting to minor changes in the business environment. An issue to be addressed in future corporate law reform is the legislative introduction of compensatory liability of parent companies towards their subsidiaries. Legislative reform would have to take into account the special characteristic of Japanese parent-subsidiary groups, in which the division of powers between parent and subsidiary eschews specific directions on operations from parent to subsidiary (as in the German model), but which instead leaves the subsidiary to make operational choices. Because of this characteristic, it is difficult as a matter of proof to clearly establish that the parent has exerted ‘influence’ on the subsidiary. Therefore, a presumption that a measure which causes the subsidiary detriment while benefiting the parent is the result of influence from the parent should be introduced to address this evidentiary difficulty in the Japanese context. If compensatory liability of parent companies to subsidiaries is to be introduced, a procedure for liability suits must also be laid out. It is necessary to recognize the standing of subsidiary shareholders to bring derivative claims against directors of the parent (cf. AktG section 317 sentence 4, 309 sentence 4). To balance the competing interests of protecting trade secrets and minority shareholders while ensuring that information relevant to such shareholder suits is disclosed, Japan should draw on the evolving European experience and make full use of the system in which the court appoints inspectors in situations giving rise to the suspicion that subsidiary interests are harmed in a parent-subsidiary transaction or other similar situations. In addition, where subsidiary interests are continually harmed under the comprehensive direction of the parent company and the compensatory mechanism cannot function as designed, minority shareholders of the subsidiary should be granted the right to withdraw from the subsidiary with compensation. This is because a structure of dominance of this type is of the parent’s making, and because the party that benefits from such a structure of dominance is ordinarily the parent.