大阪大学　数理・データ科学教育研究センター
Center for Mathematical Modeling and Data Science,The University of Osaka

Why do firms prefer after-hours disclosure? Evidence from Japan

Jin Huixing (東京都立大学)

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4. Why do firms prefer after-hours disclosure? Evidence from Japan

大阪大学 数理・データ科学セミナー 金融・保険セミナーシリーズ 第153回

Why do firms prefer after-hours disclosure? Evidence from Japan

Jin Huixing (東京都立大学)

The Tokyo Stock Exchange does not require firms to pre-notify the exchange before releasing material information during trading hours. Nevertheless, more than 80% of Japanese firms announce their quarterly earnings after the market closes. We exploit the TSE’s extension of its closing-time from 3:00 p.m. to 3:30 p.m. in November 2024 to examine whether firms deliberately choose after-hours announcements. The extension reduces the proportion of after-hours announcements by approximately 10%, suggesting that operational constraints had previously forced some announcements to occur after trading hours. Importantly, about 40% of companies announce earnings immediately after the market close in both the pre- and post-extension periods, implying that many firms deliberately prefer after-hours announcements. After-hours announcements are associated with higher stock return volatility and lower stable shareholder ownership, indicating that during-hours announcements are particularly costly for firms exposed to price fluctuation risks. Although positive earnings surprises are somewhat more likely to be disclosed during trading hours than negative ones, the influence of information content is modest. Overall, our findings suggest that firms voluntarily impose a quasi-trading halt on themselves, even in the absence of a formal pre-notification requirement.