The Biggest Fund Wins, and Then Keeps WinningWide moat
BlackRock (BLK) — moat facet
Two identical funds, one basis point apart, and the larger one gets larger — which is why the fee war never moved the share.
Two funds hold the same index, charge within a basis point of each other, and have wildly different futures. The larger one gets larger.
The mechanism is mundane. Market makers quote tighter spreads on securities they can hedge cheaply, which means securities that trade often. Options market makers write contracts on funds with liquid underlyings, and the existence of a listed options market attracts a whole class of institutional user who would otherwise not be there. Securities lending desks pay more to borrow shares of a fund that is widely held. Model portfolios and separately managed account platforms default to the ticker their trading desk already knows. Each of those makes the fund a slightly better instrument, which brings more assets, which makes it slightly better again.
BlackRock took $367 billion into US-listed iShares and $160 billion into international listings in 20251. Those are not marketing wins. They are the visible output of a machine that has been running for twenty years.
The clean test is the counterexample. A competitor launching an identical fund at a lower fee is doing the one thing that cannot dislodge an incumbent here, because the fee is already a rounding error against the trading cost. What can dislodge it is a genuinely new exposure where nobody has the incumbency yet — which is why the interesting competitive action in ETFs is always in new categories, and almost never in the old ones.
$367 billion into US-listed iShares and $160 billion internationally in one year. Every dollar of that widens the spread advantage over the identical cheaper fund next to it, and nothing a competitor can do about price reverses it.
$289B into equity, $175B into fixed income, $35B into digital assets and $25B into commodities - $367B into US listings and $160B internationally. Flow of this size into already-deep pools is what compounds the liquidity advantage.
Source: BlackRock Form 10-K, fiscal year 2025 ↗- ReportedBlackRock took $367 billion into US-listed iShares and $160 billion into international listings in 2025BlackRock, Inc. Form 10-K, FY2025, Item 1 Business — iShares ETF AUM $5.5 trillion with $527 billion of 2025 net inflows: equity $289,263M, fixed income $175,328M, digital assets $34,763M, commodities $25 billion, multi-asset $1,978M; US-listed ETF AUM $3.9 trillion with $367 billion of inflows and international listings $1.6 trillion with $160 billion; equity ETF AUM rose from $3,106,398M to $4,006,014M on $580,684M of market change and $29,669M of FX, fixed income from $985,652M to $1,205,953M, digital assets from $55,306M with a negative market change; 2025 equity net inflows $220 billion overall, being $289 billion into ETFs against $55 billion and $14 billion of outflows from non-ETF index and active; fixed income net inflows $164 billion, $175 billion into ETFs and $29 billion into active; "approximately half of BlackRock's equity AUM is tied to international market strategies, including emerging markets, which tend to have higher fee rates than US equity strategies" — FY2025 · publ. February 2026 · source ↗