Carl Icahn

Icahn buys undervalued companies with bad management. His thesis is consistently the same: there is enormous value being destroyed by entrenched executives who are more interested in keeping their jobs than returning value to shareholders.

He buys enough stock to force a confrontation. Sometimes management cleans itself up just from the threat of his involvement.

Sometimes he installs new people. Sometimes he forces a full sale of the company.

His version of value investing is more aggressive than Graham''s or Buffett''s. He doesn''t wait for the market to recognise value.

He forces the recognition. He is comfortable with conflict in a way most investors are not.

He sees confrontation with management as part of the job — not an unfortunate side effect of it.

Bill Ackman

Ackman is a concentrated, long-hold, activist investor. He typically owns 5–10 positions at a time — sometimes fewer.

Each one involves exhaustive research. If he's buying, he has usually already built a 100-slide deck explaining exactly what's wrong with the company and exactly what needs to change to fix it.

His style is the opposite of index investing. He wants a controlling voice at the table.

He wants to talk to the CEO. He wants the board to change.

That's the "activist" part — he's not just buying a stock and hoping it goes up. He's buying it with a plan to force the thing that will make it go up.

The strategy works until it doesn't. When the thesis is right, he wins massively.

When the thesis is wrong and he's also very public about it, the losses are spectacular.

Carl Icahn

He genuinely believes management teams destroy shareholder value through complacency, self-dealing, and entrenchment. He sees himself as a corrective force — not a vulture, but a mechanism by which markets hold management accountable.

Whether that''s how it looks from inside the companies he targets is a different question. His rules: buy when nobody else wants it, apply pressure to unlock the value, sell when the value is recognised.

Don''t get sentimental about positions. Don''t let management tell you the company is more complex than it looks.

Bill Ackman

Ackman's core belief is that markets frequently misprice assets when the story around them is either too negative or too complicated. He looks for businesses he can understand deeply, with a gap between what the market thinks they're worth and what he thinks they're worth.

He's talked extensively about asymmetric bets — situations where you can be wrong and lose a small amount, but right and make a lot. He believes activist investing works because most company boards are too comfortable and most CEOs have too little accountability.

He thinks public pressure, when backed by real analysis, is a legitimate tool for creating value. Whether that makes him a hero or a villain depends on which company you ask.

Carl Icahn

He concentrates. He uses leverage.

He''s comfortable with positions that make other investors deeply uncomfortable. He''s also comfortable being wrong in public — he''s had positions go spectacularly badly and he doesn''t hide from them.

His Hertz position went bankrupt during COVID. His Herbalife long was a very public, very watched position on the opposite side of Bill Ackman''s short.

He doesn''t bluff. When he says he''s going to fight, he fights.

Bill Ackman

Ackman runs highly concentrated books and uses leverage. That's the opposite of conservative.

He'll put 20–30% of the fund in a single position if he believes in it. He also uses options and credit derivatives — his March 2020 COVID hedge was built using credit default swaps, instruments most retail investors have never heard of.

He famously described his risk approach as: "I only invest when the downside is zero and the upside is unlimited" — which sounds great until you lose $4 billion on one trade. The honest version is: he's a high-conviction investor with a high tolerance for pain on the way to being right.

Carl Icahn

He lives in Sunny Isles Beach, Florida. He works ferociously hard and has done so into his late 80s.

He''s a hands-on manager — not someone who delegates. He famously said: "If you want a friend on Wall Street, get a dog." He has a Maltese named Tiger.

He''s been a prolific poker player and was once considered one of the best amateur players in New York. He remarried in 2012; his current wife is Gail Golden.

He''s given some money to charity but not at the scale of Buffett or Gates — he''s made no secret of prioritising returns over philanthropy.

Bill Ackman

Ackman has a taste for the finer things and doesn't pretend otherwise. He owns a large Manhattan apartment, he's been photographed at high-end charity events, and his social circle overlaps with New York media, finance, and political elite.

He and his second wife, Neri Oxman, have a high public profile — she's a former MIT professor and design pioneer. He gave $25 million to Harvard (his alma mater), though the relationship became famously strained in 2023 when he led a very public campaign against Harvard's president over campus antisemitism, ultimately contributing to her resignation.

He is not a guy who stays quiet about anything.

Carl Icahn

Apple. In 2013 he disclosed a $1.5 billion stake in Apple and published an open letter to Tim Cook urging a larger share buyback.

Apple eventually announced a significantly expanded buyback program. The stock rose.

Icahn made approximately $2 billion on the position. He didn''t have to engineer a hostile takeover — just making his involvement public was enough to move one of the largest companies in the world.

Bill Ackman

The COVID hedge in March 2020 is the one. As markets started selling off in late February, Ackman quietly spent $27 million buying credit default swaps — basically insurance on corporate bonds defaulting if the economy collapsed.

He then went on CNBC on March 18, 2020, visibly emotional, and said "hell is coming." The market kept dropping. Three weeks later, he unwound the trade.

The $27 million had turned into $2.6 billion. That's roughly a 100x return in under a month.

He used the proceeds to buy stocks at the market bottom. He then made another fortune as markets recovered.

The whole sequence — hedge, cry on TV, buy the dip, profit — is one of the more remarkable individual trade sequences in recent hedge fund history.

Carl Icahn

TWA. He took over Trans World Airlines in 1985 using a leveraged buyout, extracted cash from the company to pay back the acquisition debt, and sold the valuable London routes to American Airlines for $445 million.

By the time he was done, TWA was a financially gutted airline. It went bankrupt in 1992, again in 1995, and was absorbed by American Airlines in 2001.

Icahn personally made hundreds of millions. The airline''s employees and creditors did not.

He''s defended his actions as legal. Legal and good for everyone are not always the same thing.

Bill Ackman

The Valeant Pharmaceuticals disaster is the one. Ackman built a massive position in Valeant starting in 2015, eventually owning about $4 billion worth of shares.

His thesis was that Valeant's model — aggressively raising drug prices and cutting R&D — was brilliant. Congress, journalists, and eventually the SEC had a different view.

The stock collapsed from $260 to under $10. Ackman spent months publicly defending the position, appearing on CNBC repeatedly to explain why it would recover.

It didn't. He finally sold in 2017 at a loss of approximately $4 billion.

It's the most expensive public loss in hedge fund activism history. The lesson he's cited: don't get emotionally attached to a position, and be faster to recognize when the fundamental thesis has broken.

Carl Icahn

Carl Icahn grew up in Far Rockaway, Queens. His father was a failed opera singer who became a synagogue cantor.

Icahn studied philosophy at Princeton — graduated 1957 — then enrolled in NYU School of Medicine before dropping out after two years to join the army. He became a stockbroker at Dreyfus & Co.

in 1961, saved $400,000, and bought a seat on the New York Stock Exchange in 1968.

He spent the early years running option arbitrage — finding and exploiting small mispricings. He was very good at it.

In the late 1970s he pivoted to a bigger game: buying large stakes in undervalued companies and forcing management changes. His first major target was Tappan Company in 1979.

By the mid-1980s he was feared by corporate boards across America. Oliver Stone''s Gordon Gekko in Wall Street is directly based on the era Icahn created.

Bill Ackman

Bill Ackman grew up in Chappaqua, New York, the son of a real estate finance chairman. He was a history major at Harvard — class of 1988 — then went straight to Harvard Business School.

His first venture was Gotham Partners, a real estate and value investing fund he started in 1992 with a Harvard classmate. It was a disaster.

The fund made concentrated bets on illiquid real estate and had to be wound down by 2003 under serious investor pressure and SEC scrutiny.

He didn't quit. In 2004 he launched Pershing Square Capital Management, this time with a clearer focus: take large stakes in companies, go public with his thesis, and use activist pressure to force management changes.

The approach worked. His reputation was built on detailed, public investment presentations — sometimes running 100+ slides — that became must-reads on Wall Street.

He turned activist investing into something that felt more like journalism than finance: research a company, find what's broken, publish everything, and bet heavily on being right.

Carl Icahn

Icahn Enterprises is his publicly traded holding company. He''s been chairman since 1987.

Some of his most famous investments: TWA, which he took over in 1985, stripped its most valuable routes to pay back the debt used to acquire it, and left financially hollowed out — it went bankrupt twice after his tenure. Texaco, where he forced a settlement that paid shareholders.

Apple, where he took a $1.5 billion position in 2013 and published an open letter to Tim Cook demanding a larger share buyback. Apple eventually expanded the buyback.

The stock rose. Icahn made roughly $2 billion on the position without engineering a hostile takeover — the threat of his involvement was enough to move a $500 billion company.

He''s also had notable losses. Hertz went bankrupt during COVID while he held a large position.

He lost hundreds of millions.

Bill Ackman

Pershing Square Capital Management is his flagship hedge fund, managing around $16 billion. His most famous public positions have included Canadian Pacific Railway, where he pushed successfully for a new CEO and a turnaround that made Pershing Square hundreds of millions.

He held a massive position in Valeant Pharmaceuticals from 2015 to 2017 — which will come up again. He took a huge bet on General Growth Properties during the 2008 financial crisis when no one else would touch it.

That one returned over $1 billion.

He has also done business on the other side: Pershing Square Holdings is his publicly listed vehicle on Euronext Amsterdam, which lets retail investors access his fund — unusual for a hedge fund of this size. He's been a major Burger King and Restaurant Brands International investor, and he backed Fannie Mae and Freddie Mac preferred shares in a long-running legal battle with the government.

Carl Icahn

Princeton University, BA in Philosophy, 1957. NYU School of Medicine, dropped out after two years.

He''s credited Princeton''s philosophy training with teaching him to question conventional wisdom — which shows up directly in how he argues with corporate boards.

Bill Ackman

Harvard College, BA in History, 1988. Harvard Business School, MBA, 1992.

He's been a major Harvard donor — and major Harvard critic — throughout his career. The irony of his most public fight being with his own alma mater was not lost on anyone.