Leopalace21's missing party walls doomed 14,599 buildings — and ended in a ¥270B takeover

In 2018 Japan's biggest rental-apartment builder, Leopalace21, admitted that party walls separating units in its buildings did not reach up to the roof space — and the problem kept spreading: partition walls, ceiling work, fire-resistance failures, wrong filler inside walls, and exterior wall assemblies that did not match the ministerial certification they were sold under. The company ordered a survey of its entire portfolio of about 39,000 buildings.

The survey confirmed the scale: by end-March 2019, 14,599 buildings — over 70% of the roughly 20,000 examined so far — had defects, 7,085 of them serious and 7,514 classed as minor. Apartments whose ceilings failed fire-resistance standards were judged dangerous, and tenants were asked to move out on short notice; by May 2019 only 56% of the portfolio had been examined and judged at all.

On May 29, 2019, the external investigation committee of lawyers delivered its report: no direct involvement of top management was proven, but it traced the defects to a corporate culture built around one-man rule. The company responded by refreshing its management. The financial bill followed: a ¥80.2 billion consolidated net loss for the year ending March 2020, its second consecutive annual loss, with repair work later interrupted by the pandemic and occupancy falling.

14,599 of ~39,000 buildings defective; ¥80.2B net loss in FY3/2020, second straight year in the red; 2026 takeover bid at ~¥270B valuation

The critical defect was invisible at handover: a party wall stopping below the attic line looks finished from inside the room.

Speed and cost were the product — mass-built rental suburbs left construction quality as the variable to squeeze.

The builder graded its own work; certification existed on paper for materials, but site practice diverged from it.

A one-man management culture, as the committee found, left nobody able to stop or even flag the shortcuts.

The cheapest product in the market is often missing something nobody can see. Hidden work has no witness, so the incentive to skip it never dies — inspections must be designed for that.

Leopalace21 spent 2019-2020 inspecting and repairing its portfolio while tenants of fire-risk units were relocated; the pandemic then interrupted repairs and pushed occupancy down, deepening the losses. The company never recovered its standing — and in September 2026 Hikari Tsushin, already holding about 18%, launched a ¥1,000-per-share takeover bid with two investment funds, valuing the company at roughly ¥270 billion, forty years after it had helped bankroll the builder's rise. The TOB runs from September 15 to October 30, 2026.