The Big Three

In 1990, the typical large American company had a shareholder base of pension funds, mutual funds, insurance companies, and direct retail. No single shareholder owned more than a few percent; the boardroom was answerable to a dispersed crowd. In 2025, the shareholder base of those same companies looks fundamentally different. The top three institutional shareholders are nearly always the same three firms: BlackRock (~$10T AUM as of recent disclosures), Vanguard (~$9T), and State Street (~$4T). They are the largest shareholder of Apple, Microsoft, Amazon, Alphabet, Meta, JPMorgan, ExxonMobil, and most of the rest of the S&P 500 simultaneously.

This is not a conspiracy. It is the mathematically necessary consequence of three trends: the rise of index investing (Vanguard, the original), the rise of low-cost ETFs (BlackRock's iShares), and the consolidation of 401(k) and IRA flows into a few dominant providers. American savers, through their retirement accounts, channel hundreds of billions of dollars per year into these three managers. The managers, in turn, vote the shares.

Why this is structurally different

In old-school capital markets, shareholders had divergent interests. Some pension funds wanted long-term yield; some hedge funds wanted quick turnarounds; some founders wanted control. The boardroom mediated these tensions. With the Big Three as universal owners, the divergence collapses. The Big Three own essentially the entire industry — every airline, every bank, every drug maker. They have no reason to want one airline to gain market share from another airline, because they own both. They have every reason to want the airline industry as a whole to be profitable.

The academic literature on this is real and growing. The "common ownership" debate — kicked off by work from José Azar, Martin Schmalz, and Isabel Tecu — has produced empirical evidence that industries with high Big Three ownership exhibit weaker price competition, higher margins, and lower R&D intensity than industries without it. The size of the effect is contested; the direction is not.

What they actually do with their power

The Big Three almost never actively try to control boards. They are passive in trading (they're index funds — they hold whatever the index holds). But they vote shares, and that voting power is concentrated.

Voting at proxy contests. When an activist investor pushes for a board seat or a corporate breakup, the Big Three's votes are usually decisive. They historically vote with management ~90%+ of the time. The exception is when something looks egregious enough to attract attention — Exxon 2021 (climate slate), Disney 2024 (Peltz). Even then, the Big Three are reluctant kingmakers.

Engagement. All three firms have "stewardship" teams that meet privately with companies in their portfolios. The content of these meetings is mostly confidential, but the agenda is roughly: governance basics (board independence, executive comp structure), and increasingly ESG-style topics (climate disclosure, workforce composition). What's discussed in those meetings has real effects on policy that don't show up in any public vote.

What they explicitly don't do: They don't generally try to set business strategy. They don't push for one company to undercut another's prices. They don't (as far as the record shows) directly coordinate industry-wide policy. The "anticompetitive" effects, if they exist, work through softer channels — management's awareness of who owns them, the lack of activist pressure that more concentrated owners might apply, and the basic fact that competing harder against your fellow Big-Three-owned rival doesn't help your Big Three owners.

The deeper structural concern

Modern American capitalism has produced an ownership structure that no political theorist would have designed. Roughly one in five dollars of American corporate equity is voted by three firms answerable to no electorate, regulated lightly, and accountable principally to the index they track. This is a serious governance question regardless of whether you think the Big Three are competent and well-intentioned (and most close observers think they are; that's not the issue).

The questions to sit with:

— Should the largest single owner of nearly every major American company be voting shares in private meetings with management?

— Should an index fund's voting power be passed through to underlying retirement-account holders? (BlackRock has actually started experimenting with this — "Voting Choice" — though take-up is small.)

— Is there any other industry where 60%+ market share for three firms wouldn't trigger antitrust attention? Why this one?

The asset-strip cousins: private equity

The Big Three are universal owners with passive strategies. Their structural cousins are private equity firms (Blackstone, KKR, Apollo, Carlyle, etc.) — which are concentrated owners with very active strategies. PE has grown from a niche corner of finance in the 1980s to roughly $13 trillion in global assets under management today. Where the Big Three sit and vote shares, PE buys whole companies, takes them off public markets, restructures them aggressively, and sells them on. That's the subject of the next lesson — and where most of the "where did the value go" stories of the last 25 years originate.