コーポレートガバナンス改革において，企業年金のアセットオーナーとしての専門性の向上が，最終受益者であり母体企業のステークホルダーでもある従業員の資産形成に寄与し，企業の中長期的な価値や株主価値の向上につながることは重要なテーマである。他方で，コーポレートガバナンスの基本的枠組みから見た企業年金の特徴に鑑みると，母体企業と企業年金の受益者との間に生じ得る利益相反の潜在的可能性を十分にふまえたうえで慎重に議論すべき論点でもある。
本研究では，母体企業の財務的意思決定が企業年金政策に与える影響に関する国内外の研究動向を整理することを通じて，企業年金とコーポレートガバナンスのテーマが持つ特殊性の論点を浮き彫りにするとともに，日本企業の退職給付関連データを用いた若干の実証的検討を試みた。
具体的には，退職給付会計基準導入後の日本企業のデータを用いて，株主から従業員への実質的なリスクシフトの傍証が確認されるかどうかを，年金資産の期待運用収益率と母体企業の株価との関係を調べることを通じて検討した。その結果，積極的な期待運用収益率を設定する企業ほど，時価簿価倍率が高くなることが確認された。さらに，このような関係は，企業年金の積立水準が相対的に厳しい状態にあり，母体企業の収益性が相対的に低水準にあるような企業群が牽引していることも分かった。
さらに，母体企業の株主構成に着目した分析を行ったところ，外国人や機関投資家の持株比率の高い企業群においては，こうしたリスクシフトによる株主価値の増加効果は大きく減衰することも確認された。この結果は，母体企業に対するガバナンスの程度が，企業年金政策上のリスクシフトのインセンティブにも影響を及ぼす可能性を示唆するものであり，興味深い。すなわち，母体企業へのガバナンスが不十分であり，過少投資が懸念される企業においては，経営者裁量下にある期待運用収益率の設定を通じた株主から従業員へのリスクシフトの相対的価値が高く，既存株主を「過度」に利する可能性が懸念される。
In corporate governance reform, it is an important topic that the improvement of expertise as asset owners of corporate pensions contributes to the asset formation of employees, who are the ultimate beneficiaries and stakeholders of the mother company, and leads to the enhancement of the medium- and long-term value of the company and shareholder value. On the other hand, in view of the characteristics of corporate pensions from the perspective of the basic framework of corporate governance, it is also an issue that should be carefully discussed in full consideration of the potential conflicts of interest that may arise between the mother company and the beneficiaries of the corporate pension.
This study attempts to highlight the relation between corporate pensions and corporate governance through a review of domestic and international research trends on the impact of the financial decisions of the mother company on corporate pension policies, as well empirical studies using retirement benefit (corporate pensions) -related data from Japanese listed companies.
Specifically, using data from Japanese firms after the introduction of the accounting standard for retirement benefits (corporate pensions), this study examines whether there is evidence of a substantial risk shift from shareholders to employees by examining the relationship between the expected return on plan assets and the stock price of the parent firm. This study finds that the firms that set an aggressive expected return on investment have higher market value book value multiples. Furthermore, This study finds that such a relationship is driven by a group of firms in which the level of corporate pension funding is relatively tight and the profitability of the mother firm is relatively low.
In addition, the analysis focusing on the shareholder composition of the sponsoring company confirms that the effect of the increase in shareholder value due to such risk shifting is greatly attenuated in the group of companies with high shareholding ratios of foreign and institutional investors. The results are interesting because they suggest that the degree of governance towards the sponsoring firm may also influence the incentives for risk shifting over corporate pension policy. In other words, in firms with poor governance to the sponsoring firm and concerns about under-investment, the relative value of risk shifting from shareholders to employees through the setting of expected return on investment, which is under management's discretion, is high, and there are concerns about the potential to "excessively" benefit existing shareholders.