13 Who these investors are

Not Every Big Investor Is Doing the Same Job

“Institutional investor” covers three very different businesses. The quickest way to tell them apart is to count how many companies each one holds.

15,445

companies in Citadel’s book. Bill Ackman’s Pershing Square holds 16.

Companies held At 30 June 2026

Stock pickers

Hedge funds and family offices

A few dozen companies, chosen deliberately. Every trade is a decision worth reading.

Passive funds

Index and tracker managers

Own the whole market on purpose, because a tracker has to. They are not taking a view.

High-turnover firms

Quant funds and market makers

Hold almost everything for days rather than years. The positions are trading inventory.

The concentrated funds nobody writes about

None manages more than $13bn and none is a household name, yet all three have the same largest holding, SanDisk, and each opened it within the last four quarters.

11%

Whale Rock

in SanDisk · 42 holdings

21%

AIGH Capital

in SanDisk · 61 holdings

36%

Sassicaia

in SanDisk · 57 holdings

Check which group a fund sits in before reading anything into its trade. A stock picker adding a position has made a choice. A market maker doing the same has taken in inventory.