Test detail

Based on collected information, I will analyze this structurally and multidimensionally.

Big Three Control Power: "Result of Diversification" or "Substantive Concentration of Control"?

I. First, confirm the "facts": How concentrated is this?

Vanguard, State Street, BlackRock voting is particularly significant. These three companies constitute top shareholder groups in over 75% of S&P 500 enterprises.

BlackRock, Vanguard, State Street Global Advisors collectively manage over $30 trillion in assets and control approximately 74% of the U.S. equity ETF market. Combined, the Big Three represent the largest shareholder in approximately 88% of S&P 500 companies, exercising roughly one-quarter of all proxy voting power at these companies' shareholder meetings.

According to research by Bebchuk and Hirst, the Big Three's combined holdings in S&P 500 companies expanded from 13.5% in 2008 to 22.2% in 2023, with over 438 companies having combined Big Three stakes exceeding 20%.

In 1950, individuals directly held 90% of U.S. equities, but by 2023, institutional investors held over 70%. This transition represents a shift in corporate voting rights from hundreds of millions of dispersed shareholders to a handful of institutional investors.

II. The Structure of "Merely a Result of Diversified Investment"

The Big Three are victors of index investing and passive management. They became major shareholders not through strategic control ambitions but through steady, mechanical growth of index funds they manage. This differs fundamentally from strategic acquisitions or hostile takeovers.

As of June 2025, BlackRock manages $12.53 trillion, Vanguard over $9 trillion, and State Street approximately $4.3 trillion, collectively managing about 78% of U.S. ETF assets. Passive funds exceeded 50% of U.S. equity fund assets in 2023, with share continuing to expand, further concentrating voting rights in the Big Three.

Legal structure also presents an important analytical point. The $22 trillion in assets managed by BlackRock, Vanguard, and State Street are ultimately owned by fund investors, not the three firms themselves. The Big Three hold these shares and exercise voting rights merely as fiduciaries.

III. The Heart of "Substantive Concentration" Critique: Proxy Voting Reality

This is the crux of the question: whether "diversified investment result" explanation holds depends on in whose interest and how these fiduciaries exercise proxy rights.

❶ "Management Deference" as Structural Problem

The Big Three vote on thousands of proxy proposals annually. In the 2025 proxy season, support for management proposals reached 98.7%, up from 96% in 2023. Conversely, support for shareholder proposals stood at merely 7.5%.

Voting in line with management recommendations is not a "passive" act—it is active exercise of control. Voting management-recommended slates represents exactly the same "exercise of control" as voting differently.

❷ Voting Power Exceeds Ownership Ratio

The Big Three collectively own approximately 15–16% of S&P 500 equities, yet Bebchuk and Hirst's research shows BlackRock and Vanguard alone account for over 20% of 2021 proxy voting despite holding only ~12% stakes.

This occurs because individual investors and foreign investors frequently do not exercise voting rights, while the Big Three exercise voting rights on virtually all owned shares.

If current trends continue, Bebchuk and Hirst estimate the Big Three's voting share in S&P 500 companies will reach approximately 34% in ten years and 41% in twenty years.

In this "Giant Three scenario," three investment managers would control shareholder voting on essentially all major U.S. public companies lacking controlling shareholders.

❸ ESG Proxy Voting "Political Volatility" as Indicator

Support for environment and social-related shareholder proposals plummeted in 2023: BlackRock 7%, Vanguard 2%, State Street ~20%. This indicates the Big Three's preferences substantively influence corporate policy priorities and disclosure direction.

Vanguard and BlackRock explicitly reduced ESG proposal support, judging many proposals as "excessively prescriptive" or "duplicative." This demonstrates the Big Three actively selecting corporate governance direction through their voting choices.

Bebchuk and Hirst conclude the Big Three's substantive proxy voting power is considerable and likely to persist and expand. Furthermore, through both action and inaction, this power grants them substantial influence over corporate outcomes.

❹ Common Ownership Problem

"Common ownership theory" posits that a single investor holding minority stakes in multiple competitors within an industry creates anticompetitive effects, linking collective stock ownership to higher consumer prices and executive compensation.

The situation where Big Three holdings in competing firms are substantial enough to constitute common ownership did not exist twenty years ago.

IV. "Decentralization" Attempts: Pass-Through Voting Reality and Limitations

In response, all three firms introduced mechanisms allowing investors to exercise voting rights themselves.

From 2022–2023, Vanguard, BlackRock, and State Street began offering institutional and individual investors options to opt out of stewardship programs and exercise proxy rights independently.

In May 2025, Vanguard announced expansion of this program to approximately $1 trillion in assets and roughly 10 million investors.

However, actual participation remains perfunctory. According to Vanguard, participation in this program during the 2024 proxy season reached merely 2% of eligible investors.

During the 2024 proxy season, only approximately 40,000 of Vanguard's 2 million eligible investors (2%) participated in the pilot program. Despite initial enthusiasm for pass-through voting, actual effectiveness remains limited—Vanguard cast zero support for 400 ESG-related environmental and social shareholder proposals.

V. Comprehensive Judgment: "Diversification Result" and "Substantive Control" Are Not Binary

Based on the above analysis, I present the structural conclusion in the following table:

In conclusion: While Big Three majority shareholding is certainly a "structural consequence" of passive investing, the "substantive concentration of control" superimposed upon it cannot be denied. When BlackRock, Vanguard, and State Street collectively hold 20–25% of S&P 500 companies, they are no longer "passive investors" in the colloquial sense. They are the largest shareholders seated at the table when boards make decisions on executive compensation, capital allocation, mergers, and competitive strategy.

What proxy voting practices reveal is a divergence between two questions: "For whom are they voting (fiduciary duty)?" and "What are they actually deciding (substantive control)?". Being passive in approach does not mean not exercising voting rights. Now that this voting power has expanded to scales influencing corporate governance direction, the "diversification result" explanation may serve as a starting point but cannot exempt from responsibility.

BlackRock, Vanguard, and State Street's status as top shareholder groups in many S&P 500 companies is primarily attributed to diversified investment results. These firms invest broadly across multiple holdings through index-tracking funds. As a result, they frequently become major shareholders in many companies.

Diversified Investment

• Diversified Investment is a strategy that mitigates risk while investing across broad markets, and represents one reason these firms are major shareholders in S&P 500 companies.
• Through index funds and ETFs distributing investments across multiple companies, these firms naturally accumulate large stakes in numerous companies.

Proxy Voting Practice

• Proxy Voting practice shows the Big Three generally maintain neutral positions and rarely directly intervene in company operations.
• On significant matters, they vote considering environmental, social, and governance (ESG) factors.
• While they can exercise influence on corporate initiatives, this does not necessarily aim at substantive control.

Conclusion

• Their influence is increasing, but they do not primarily target direct corporate control; they remain focused primarily on diversified investment objectives.
• However, their scale and influence cannot discount potential significant impact on important corporate decisions.

Ultimately, impact depends on how these asset managers exercise proxy voting, though current understanding generally characterizes this as strategic investment implementation rather than control concentration.

The question of whether BlackRock, Vanguard, and State Street's (collectively "Big Three") position as top shareholder groups in S&P 500 companies represents "merely a result of diversified investment" or "substantive concentration of control" reveals, from proxy voting practice perspectives, a situation that can be characterized as "concentrated control with quasi-concentrated aspects, yet presenting complex dimensions."

Concentration as Diversification Result: These major asset managers hold significant equity stakes in S&P 500 firms primarily through expansion of their index funds. They manage portfolios by aggregating funds from millions of individual investors and investing in market indices like the S&P 500 in a tracking format. Consequently, they acquire large shares in index constituent companies. This represents aggregation of distributed individual diversified investments through these fund vehicles. The Big Three collectively manage nearly $11 trillion in equity assets.

Proxy Voting Practice and Control Implications: However, massive equity holdings carry enormous proxy voting power.

• Concentrated Voting Rights: In a 2019 paper, Lucian Bebchuk and Scott Hirst demonstrated that the Big Three account for approximately one-quarter of voting rights at S&P 500 shareholder meetings, with projections suggesting they may approach 40% within twenty years.
• Stewardship Team Proxy Voting: These firms exercise proxy voting on behalf of investors on hundreds of thousands of proposals annually. BlackRock, for instance, has approximately 70 personnel managing this responsibility. Given this team's vast workload, they heavily rely on external proxy voting advisory firms (Institutional Shareholder Services and Glass Lewis) for research.
• Pro-Management Voting Patterns: Research by Bebchuk and Hirst (2019) indicates index funds demonstrate lower likelihood of voting against management on contentious corporate governance matters compared with active funds. They also promote lower board independence and weaker compensation-performance linkages. Underlying this is "agency cost" theory: index funds lack direct incentives for individual company performance improvement and prioritize low-cost operations, thereby reducing stewardship investment.
• Individual Company Engagement Limitations: Because Big Three invest across numerous companies, adequate monitoring and engagement resources for individual firms become challenging. However, alternative perspectives suggest that given massive management assets and major stakes, index funds have substantial economic incentives for productive engagement.
• Proxy Voting Choice Programs: Recently, BlackRock and Vanguard have introduced programs allowing fund investors to select proxy voting policies independently (Voting Choice / Investor Choice programs). By mid-2026, Vanguard's program encompassed approximately $4 trillion in assets with over 500,000 participating investors. BlackRock has committed approximately $923 billion in index equity assets to similar initiatives by June 2026. State Street has initiated comparable pilot programs in certain ETFs. These represent responses to "control concentration" criticisms by returning voting authority to individual investors.
• ESG Voting Differentiation: ESG-related shareholder proposal voting shows variation among Big Three. In 2023 analysis, BlackRock and State Street supported majority ESG proposals while Vanguard opposed nearly three-quarters. Voting patterns also vary by specific themes (human rights, climate change, etc.).

Conclusion: The Big Three's top shareholder status in S&P 500 companies fundamentally represents aggregation through index funds of distributed individual diversified investments. However, the concentrated proxy voting power this aggregated shareholding creates represents substantive corporate influence approaching "control concentration". As fiduciaries seeking client value maximization, their proxy voting at times appears management-favoring, and voting patterns are currently shifting through investor proxy choice provision initiatives. Critically, they do not directly "own" companies but hold shares on behalf of fund investors, which remains essential to understanding their role.

Diversified investment results have created massive holdings generating concentrated voting rights, but Big Three (BlackRock, Vanguard, State Street) proxy voting practice primarily reflects "passive stewardship" supporting management and boards, rather than active control or strategy alteration.

Holdings Background and Scale

• Big Three constitute top (or upper-tier) shareholders in many S&P 500 companies, collectively holding approximately 20% of shares, with proxy voting share reaching approximately 25% in many cases. This results from passive index fund/ETF investing rather than individual active decisions.
• Holdings represent customer assets (individual investors, pension funds) under management; Big Three themselves do not directly capture economic benefits.

Proxy Voting Practice Reality (2023–2025 proxy season data-focused)

• Management Proposal Support Rate Extremely High: 2025 proxy year Big Three average 98.7% (prior year 98.0%, 2023: 96.0%). Top 10 asset managers average 97.5%, with Big Three showing even stronger management alignment. Voting data consistently shows management-favorable patterns.
• Shareholder Proposal Support Lower: Particularly ESG-related at single digits (2025 Big Three average 7.5%, declining year-over-year). Governance proposals receive relatively greater support, though overall cautious approach.
• Director Elections: S&P 500 BlackRock approximately 98.7%, Vanguard 99.3%, State Street 95.35% support (2024-2025 season). Overall management support dominates.
• Proxy Contests (activist opposition): Over past decade, Big Three rarely fully support activist slates (BlackRock ~2 instances, Vanguard/State Street few instances). Support at most 1–2 nominees, reflecting management-favorable judgment.
• ESG Stance Reversal: Policy moderation/elimination on climate and diversity, Climate Action 100+ departures visible. Support rate declines reflect this.

Control vs. Passive Influence

• Not substantive control: Big Three do not nominate directors or submit shareholder proposals, exercising influence through private engagement. Voting itself derives from fiduciary duty for "long-term shareholder value," typically aligning with management. ESG advocacy previously active but recently contracted due to political/regulatory pressure.
• Influence concentration exists: Scale makes voting outcome-determinative (particularly in close contests). This represents "passive power" as diversification byproduct, distinguishing it from active "control" strategy. Some researchers like Bebchuk note Big Three stewardship underinvestment and excessive management deference.
• Pass-Through Voting Evolution: Recent initiatives offering individual investors voting choice options (Voting Choice/Investor Choice programs) are expanding, with Vanguard showing increased participation though eligible asset proportions remain limited. This gradually dilutes Big Three direct influence.

Conclusion

From proxy voting practice perspective, this represents "concentrated passive influence"—concentrated shareholding from diversification results generating concentrated voting, but Big Three proxy voting remains primarily management-supporting "passive stewardship" rather than active S&P 500 company control. Default voting supports management, shareholder intervention limited absent clear shareholder value or governance issues. ESG themes show recent moderation toward caution/neutrality, reflecting fiduciary asset management character. However, scale-derived influence remains real with future pass-through voting expansion or regulatory changes potentially shifting this calculus.