TOKYO — Japan is preparing to radically reshape one of Asia’s most important stock-market benchmarks, with 683 companies earmarked for eventual removal from the TOPIX index as Tokyo pushes listed companies to become more liquid, more valuable and more attractive to global investors.
The overhaul is one of the biggest changes in the history of the Tokyo Stock Exchange’s TOPIX benchmark.
And it could have consequences far beyond the index itself.
The companies facing removal represent roughly one-third of current TOPIX constituents, while only 35 companies are being added under the new selection criteria. The index is ultimately expected to shrink from 1,636 companies to at least 986, although the final number will depend on a later reassessment.
The changes are not designed simply to make TOPIX smaller.
Japan is trying to force its corporate sector to become more investable, more competitive and more focused on shareholder value.
And there may be a major winner hiding inside the reshuffle:
Japan’s biggest and fastest-growing companies—particularly those benefiting from the AI boom—could gain even greater influence over the benchmark.
Japan Is Taking a Knife to TOPIX
TOPIX, short for the Tokyo Stock Price Index, is one of Japan’s most important equity benchmarks.
Unlike the Nikkei 225, which is weighted according to share prices, TOPIX is designed to represent a much broader cross-section of Japan’s listed companies.
That breadth has historically been one of its strengths.
It has also become a weakness.
TOPIX contained 1,636 stocks at the end of August 2026, including hundreds of smaller companies that can be difficult and expensive for large institutional investors to track efficiently.
Now Japan Exchange Group is changing the rules.
The first stage of the reform reduced the number of TOPIX constituents from roughly 2,200 to around 1,700 and was completed in January 2025.
The second stage is much more aggressive.
The first periodic review under the new system has identified 683 existing constituents for eventual removal, while 35 companies have been selected for inclusion.
This Is Not an Immediate Mass Eviction
One important distinction is being lost in some of the headlines.
The 683 companies are not all being instantly deleted from TOPIX.
Japan Exchange Group is using transitional measures to reduce market disruption.
For companies that fail the new criteria, their index weightings will be reduced gradually, with the transition extending through July 2028. A reassessment in October 2027 will determine whether some companies can avoid further reductions by meeting the continuation criteria.
That gives affected companies roughly two years to improve their market position.
It also gives investors time to adjust.
But the message from Tokyo is unmistakable:
Companies that remain too small, too illiquid or insufficiently attractive to investors will no longer automatically have a place in Japan’s flagship broad-market index.
What Does a Company Need to Stay?
The revised methodology puts greater emphasis on liquidity and free-float market capitalization.
Under the new continuation criteria, companies generally need an annual traded-value ratio of at least 0.14 and must rank within the top 97% by cumulative free-float-adjusted market capitalization among qualifying companies.
New entrants face an even higher threshold, requiring them to fall within the top 96%.
The objective is straightforward:
TOPIX should contain companies that investors can actually buy and sell efficiently at meaningful scale.
That sounds technical.
But for companies sitting near the bottom of the index, it could become a major financial problem.
Getting Kicked Out Can Trigger Forced Selling
TOPIX is not just a list of Japanese companies.
It is a benchmark for enormous pools of investment capital.
Japan Exchange Group says assets linked to TOPIX—including ETFs, mutual funds and pension trusts—stood at approximately ¥160 trillion ($1 trillion) at the end of June 2026.
That means index membership can matter enormously.
When a stock is removed from a major benchmark, passive funds designed to track that benchmark generally have to reduce or eliminate their positions.
When a company is added, those same funds may need to buy it.
That creates potentially significant buying and selling pressure around index changes.
The Japan Times, citing analysts, reported before the announcement that removal from TOPIX could cut companies off from an estimated $1 trillion in passive assets tracking the benchmark, potentially weighing on their share prices.
For some smaller Japanese companies, therefore, remaining in TOPIX is not merely a prestige issue.
It can directly affect liquidity, investor visibility and access to capital.
But Here Is the Twist: The Market Impact May Be Smaller Than It Looks
There is a paradox in the numbers.
Almost 700 companies could eventually leave the index.
Yet their collective impact on TOPIX’s overall value may be relatively limited.
UBS analysts cited by the Financial Times estimate that the stocks at risk of exclusion represent less than 3% of TOPIX’s total market capitalization.
That means the reshuffle is enormous in terms of the number of companies affected, but potentially much less dramatic in terms of the index’s overall value.
Why?
Because many of the companies being removed are small.
The companies remaining in TOPIX will therefore account for a much larger share of the benchmark’s market capitalization.
That is exactly what Japan’s exchange wants.
The Big Get Bigger
One of the most important consequences could be an increase in the relative influence of large Japanese companies.
Goldman Sachs analyst Bruce Kirk told the FT that the focus on free-float weighting is likely to increase the influence of large-cap companies, many of which are benefiting from the AI investment boom.
That could further concentrate investor attention on Japan’s largest technology, financial and industrial companies.
Among the heavyweight names in TOPIX are companies such as Mitsubishi UFJ Financial Group, Toyota Motor and SoftBank Group.
The implication is significant.
As smaller companies disappear from the benchmark, the performance of large, liquid corporations could become increasingly important to investors tracking Japan’s broad market.
AI Could Become an Even Bigger Force
Japan’s stock market has increasingly benefited from the global artificial-intelligence investment cycle.
Semiconductor companies, technology suppliers, robotics businesses and other firms connected to AI infrastructure have attracted substantial investor attention.
The TOPIX reforms could amplify that trend.
If large AI-linked companies represent a greater proportion of the index, their earnings and valuations could have a larger effect on overall TOPIX performance.
That does not mean Japan is deliberately redesigning TOPIX to favor AI companies.
The reform is based on liquidity and market capitalization criteria.
But the outcome could nevertheless be an index with greater exposure to the companies already benefiting from one of the world’s biggest investment trends.
The New Additions Tell Another Story
The reshuffle is not only about who is leaving.
35 companies are being added.
Among the incoming names are Trial Holdings, Workman and autonomous-driving company Tier IV, according to Reuters reporting carried by The Straits Times.
The Japan Times also reported additions including McDonald’s Holdings Company Japan and Ferrotec.
That demonstrates another principle behind the overhaul.
TOPIX is not simply becoming a collection of giant corporations.
Companies can earn a place through stronger liquidity and market characteristics even if they are not among Japan’s largest blue-chip names.
The goal is a benchmark that is smaller but more investable.
Corporate Japan Is Being Put Under Pressure
The index reform is part of a much broader transformation taking place in Japan’s equity market.
Japanese authorities and the Tokyo Stock Exchange have spent years pushing companies to improve corporate governance, communicate more effectively with investors and make better use of their capital.
The exchange’s broader reform campaign is aimed at improving the attractiveness of Japanese equities to both domestic and international investors.
The pressure has already produced major changes.
Companies have increasingly announced share buybacks, higher dividends and plans to unwind cross-shareholdings.
The underlying message is that Japanese companies should no longer assume investors will tolerate chronically low returns simply because they are established businesses.
The TOPIX reform takes that philosophy one step further.
If investors cannot efficiently trade your shares, you may not belong in the benchmark they use to represent Japan’s market.
Smaller Companies Now Face a Choice
For the 683 companies facing removal, the next two years could become a race against the clock.
They can attempt to improve their market capitalization.
They can increase liquidity.
They can expand their free float.
They can attract more investors.
Or they can accept that they may eventually fall outside one of Japan’s most important market benchmarks.
The 2027 reassessment is therefore crucial.
Companies that improve enough to meet the continuation criteria can stop the phased reduction in their TOPIX weighting.
Those that do not will continue moving toward zero weight.
Why This Matters to Foreign Investors
For global investors, the reform could make Japan’s equity market easier to navigate.
A benchmark containing fewer small, illiquid companies should theoretically be cheaper and easier for passive funds to replicate.
Japan Exchange Group explicitly says the reforms are designed to improve TOPIX’s functionality as an investable index, while maintaining broad market representation.
That could strengthen Japan’s appeal at a time when international investors are increasingly interested in the country’s corporate-governance reforms.
It could also make the benchmark more closely reflect where large pools of investment capital are actually flowing.
Japan Is Trying to Change Its Investment Culture
The most interesting part of this story may not be the number 683.
It is what the number represents.
For decades, Japan’s stock market was criticized for carrying companies that were small, inefficiently managed or insufficiently focused on shareholder returns.
The TOPIX overhaul represents a structural attempt to change that.
The exchange is effectively telling listed companies:
Being listed is not enough. Being part of a major benchmark is not guaranteed. You have to remain investable.
That is a major philosophical shift.
The $1 Trillion Question
Because TOPIX is linked to roughly ¥160 trillion of passive assets, changes to its composition can influence where enormous amounts of capital ultimately flow.
The biggest beneficiaries could be companies that remain in the index and gain a larger relative weighting.
The biggest losers could be small companies whose shares become less visible to institutional investors.
And the ultimate winner could be Japan itself—if the reform succeeds in forcing corporate Japan to become more competitive.
But there is no guarantee.
An index can change its constituents.
It cannot force companies to grow.
It cannot manufacture higher profits.
And it cannot make investors buy a stock simply because it remains in TOPIX.
The Bottom Line
Japan is undertaking one of the most ambitious reforms of its main stock-market benchmark in decades.
683 companies have been earmarked for eventual removal, while 35 will join TOPIX. The index is expected to shrink from 1,636 current constituents to at least 986 after the transition, although the final composition will depend on the subsequent review.
The changes will happen gradually rather than through an overnight purge, with affected stocks being phased down through July 2028 and reassessed during the transition.
For the Japanese companies being removed, the clock is now ticking.
For investors, the reform could make TOPIX more concentrated in large, liquid businesses—and potentially increase the influence of companies benefiting from Japan’s AI and technology investment cycle.
And for corporate Japan, the message could not be clearer:
The era when simply being listed was enough may be coming to an end.
The next question is the one investors will be watching most closely:
Which of the 683 companies can fight their way back before the index doors finally close?
