For companies that have left a price-to-book ratio (P/B) below 1.0x unaddressed for more than three years, market judgment can become visible well before the share price itself deteriorates further — often through an activist investor's large shareholding report. Leaving the issue unaddressed is no longer an invisible risk; it is increasingly a risk that outside parties can observe and act on.
What Does a Sub-1.0x P/B Ratio Actually Mean?
The price-to-book ratio (P/B) is calculated by dividing share price by book value (net assets) per share. A ratio below 1.0x means the market values the company at less than its liquidation value — that is, its net assets. In March 2023, the Tokyo Stock Exchange (TSE) called on all listed companies to disclose and implement "Action to Implement Management that is Conscious of Cost of Capital and Stock Price" (referred to below as the "TSE request"), and a sub-1.0x P/B ratio was the emblematic indicator that triggered the initiative. More than three years have now passed since that request, as of July 2026, and for companies that have made no meaningful progress, the sheer length of inaction is becoming a point that itself calls for explanation.
What Actually Happens to Companies That Leave the Issue Unaddressed?
Continued inaction on the TSE request tends to draw a progressively harder line from institutional investors and proxy advisory firms. Recommendations to vote against director election proposals at the annual general meeting (AGM), pressure to unwind cross-shareholdings, and demands for higher dividends or share buybacks are the kinds of issues that accumulate as an opening for engagement. And in some cases, this trajectory has been reported to extend as far as a large shareholding report that includes a declaration of material proposal intent. The longer the issue goes unaddressed, the more likely a company is to lose the initiative in engagement and instead find outside assessments made visible through public filings.
How Do Activist Investors Screen Sub-1.0x P/B Companies?
The screening criteria of individual funds are not disclosed, so no definitive statement can be made. That said, factors commonly cited as making a company more likely to be targeted for engagement or a formal proposal include, beyond a sub-1.0x P/B ratio itself: cash and securities holdings that are large relative to market capitalization, a high proportion of cross-shareholdings, and capital-efficiency plans that remain in place without accompanying numerical targets. A sub-1.0x P/B ratio is only the entry point — how many years the situation has been left unaddressed, and how specific the disclosure actually is, are what sharpen the screening further.
TSE Data: The Trend in the Number of Sub-1.0x P/B Companies and Disclosure Response Rates
On January 15, 2024, the TSE began publishing a list of companies disclosing their response to "Action to Implement Management that is Conscious of Cost of Capital and Stock Price" (Source: TSE, "Publication of List of Companies Disclosing 'Action to Implement Management that is Conscious of Cost of Capital and Stock Price,'" January 15, 2024, https://www.jpx.co.jp/news/1020/20240115-01.html). According to Nikkei's reporting on this release, roughly four in ten Prime Market companies (660 companies, 39.9%) had disclosed a response as of the end of December 2023, and at that same point roughly half of Prime Market companies were trading below a 1.0x P/B ratio (Source: Nikkei, "PBR Improvement Measures: 660 Companies Disclose Response, 40% of TSE Prime Companies," as of January 2024, https://www.nikkei.com/article/DGXZQOUB152V50V10C24A1000000/). Put the other way, roughly six in ten Prime Market companies had not yet disclosed a response at that point. As for the most current disclosure rate as of July 2026, no figure could be confirmed within the sources available for this article, and no definitive statement is made here.
What Disclosure Level Counts as "Neglect"?
Having "disclosed a response" is not the same as "not neglecting the issue." Even where disclosure exists, if it stops at a statement of policy without a stated basis for the cost-of-capital calculation or numerical targets with a timeline, outside observers tend to read it as neglect with no real progress. This is particularly true where the disclosure goes unrevised for multiple years and the P/B ratio itself shows no improvement — in that scenario, the explanation "under consideration" tends to lose credibility over time. Whether a company is judged to be neglecting the issue tends to hinge not on whether disclosure exists at all, but on whether three specific elements are present: numerical targets, a timeline, and periodic progress updates.
For Companies Starting Now, What Should Be the First Priority?
For companies that have yet to act, or whose disclosure is limited to a statement of policy, the first priority is to align the board around a shared basis for calculating cost of capital, then break down numerically what is driving the sub-1.0x P/B ratio — whether it is a profitability issue or a valuation issue. The next priority is to build improvement measures and an indicative timeline into the disclosure itself. From there, the practical priority for retaining the initiative in engagement is to establish an internal process for updating that disclosure every period, on the assumption that both existing shareholders and potential activist investors are reading it.
FAQ
Q1. What causes a sub-1.0x P/B ratio?
It is generally understood to arise from a combination of factors — low profitability (a low ROE), poor capital efficiency (excess cash or heavy cross-shareholdings), weak growth expectations, and a cautious approach to shareholder returns. Because the drivers differ from company to company, it cannot be attributed to any single cause as a general matter.
Q2. Can a company remain listed while its P/B stays below 1.0x?
The P/B ratio itself is not a criterion directly tied to continued listing requirements, and a sub-1.0x ratio alone will not result in delisting. That said, how a company responds to the TSE request does affect its standing with the market, so continuing to leave the issue unaddressed is not advisable.
Q3. Are sub-1.0x P/B companies more likely to become acquisition targets?
Because a sub-1.0x P/B ratio signals that the market values a company below its net assets, such companies are generally understood to be more likely to surface as candidates for acquirers or activist proposals. That said, since individual funds' screening decisions rely on non-public information, no company can be said to be certain to become a target.
Summary
| Item | Detail |
|---|---|
| Meaning of a sub-1.0x P/B ratio | Market valuation below liquidation value (net assets) |
| Origin of the TSE request | March 2023 — call for management conscious of cost of capital and stock price |
| Publication of the disclosure list | Published starting January 15, 2024 (TSE) |
| Disclosure response rate | Roughly 4 in 10 Prime Market companies (660 companies, 39.9%) had disclosed a response (as of end-December 2023, per Nikkei) |
| Level regarded as neglect | Multiple years with no numerical targets, timeline, or progress updates |
| Priorities for action | Quantify the drivers of the issue / disclose measures with a timeline / establish a process for periodic updates |
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