Bill Ackman (Pershing Square)
high confidence — compiled with source citation from the investment brain.
Bill Ackman (Pershing Square)
Bill Ackman (Pershing Square)
Bill Ackman founded Pershing Square Capital Management in 2004, and the corpus holds his annual shareholder letters from 2014 through 2025. The 2021 letter is the richest single document: it narrates the firm's self-described turnaround after 2015–2018 underperformance, built on four pillars — exiting the troubled Valeant long and the Herbalife short, shrinking to an investment-centric firm, stabilizing the capital base, and re-committing to "the extremely durable growth companies" that meet its core principles.
The activist model
Ackman defines Pershing Square's strategy as owning minority stakes in great businesses and using influence, not control, to create value: "acquire smaller pieces of superb businesses over which we have substantial influence, rather than controlling interests in lower quality businesses." This is the constructive-activist pole of activism-playbook — the 2021 letter even self-labels the evolution "Pershing Square 1.0" (transactional activism), "2.0" (board-level engagement), and a quieter "3.0." The other pole, activist short selling, he says was "limited to two high-profile activist short engagements" and is now "permanently retired" — the canonical example of the style the corpus tracks under kerrisdale-vs-long-only-views.
The Herbalife short
The highest-profile of those two shorts was Herbalife, which Ackman argued was a pyramid scheme. The 2015 letter states the thesis flatly: "Recent developments continue to confirm that Herbalife is a pyramid scheme." The 2021 letter reports closing the short in 2018 despite believing "substantial profits would likely have been realized", with the aphorism that you "don't need to make it back the way you lost it". The mechanics of that bet sit under short-selling-mechanics.
Asymmetric hedging, not market timing
A signature of the letters is the credit hedge: buying cheap, deeply out-of-the-money protection when conditions look fragile, then reinvesting the payoff. His analogy: "over insuring your home in advance of an expected storm where insurance is purchased with a sufficiently large deductible such that the cost is minimal and the potential payoff is large relative to the premiums paid." The 2020 letter attributes the firm's 70.2% NAV return largely to the February–March 2020 credit hedge and reinvestment rather than stock-picking — an explicit statement that hedges, not company selection, drove the year. This positions Ackman as a crowd-behavior-episodes trader who stays fully invested rather than a cycles predictor.
Cross-references and omissions
Ackman frames PSH against warren-buffett's Berkshire, arguing a closed-end fund avoids the conglomerate's tax and control constraints; the letters are the corpus's clearest articulation of a permanent-capital vehicle as an edge in index-vs-active-bets. The corpus contains only his annual letters — the 2012 Herbalife presentation and other contemporaneous documents are not present, so the short campaign is seen through his retrospective accounts and the 2015–2016 annual letters.
Investment philosophy
The compiled, source-grounded version of this investor's beliefs lives at investment philosophy.
Sources
investor-letters/PershingSquare/Letters-Markdown/2021 - Annual Letter.mdinvestor-letters/PershingSquare/Letters-Markdown/2020 - Annual Letter.mdinvestor-letters/PershingSquare/Letters-Markdown/2015 - Annual Letter.md