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.

Bill Nygren

Classic large-cap value. Nygren buys businesses trading significantly below his estimate of intrinsic value — typically at least a 40% discount.

He focuses on companies with strong management teams, high free cash flow generation, and the ability to allocate capital intelligently. He runs concentrated portfolios (20-30 stocks) and is willing to hold positions for 3-5+ years.

He is a contrarian by default — his best ideas are usually in sectors the market hates.

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.

Bill Nygren

Nygren believes the market is generally efficient but occasionally misprices individual businesses, especially during periods of fear or sector-wide pessimism. He thinks like a business buyer, not a stock trader — asking "what would a rational private buyer pay for this entire company?" He considers management quality and skill at investing company money as important as the financial statements.

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.

Bill Nygren

Moderate. Nygren runs concentrated portfolios which adds stock-specific risk, but he focuses on large-cap, established businesses with strong balance sheets.

He is not swinging at biotech startups or crypto. The risk is being early and looking wrong for extended periods while waiting for the market to recognize value.

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 is a Harvard alumnus, twice over, and gave to the school for years, 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.

Bill Nygren

Low-profile lifestyle. Based in Chicago.

Nygren does not seek media attention and rarely appears on financial TV. He writes detailed quarterly commentaries for Oakmark shareholders that are some of the best free investing education available.

He lets his long-term performance record speak for itself.

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.

Bill Nygren

His consistency over nearly three decades. While many value managers have stumbled during the growth-dominated 2010s, Nygren adapted his approach to include "modern value" — companies like Alphabet and Meta that trade at low multiples relative to their growth rates.

His willingness to evolve his definition of value without abandoning the discipline has kept Oakmark relevant.

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.

Bill Nygren

Holding financial stocks through the 2008 financial crisis. Oakmark Fund was down significantly in 2008 as bank and insurance stocks cratered.

While the long-term recovery proved him right on many of those holdings, the drawdown was painful for investors who redeemed at the bottom.

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.

Bill Nygren

Joined Harris Associates (parent of Oakmark Funds) in 1983. Became lead portfolio manager of the Oakmark Fund in 2000.

Lead manager of Oakmark Select Fund since 1996 and Oakmark Global Select since 2006. Oakmark Select Fund has returned over 11% annually since 1996 inception.

Manages over $20 billion across Oakmark strategies. Named Morningstar Domestic Stock Fund Manager of the Year in 2001.

Known for buying out-of-favor large-cap value stocks and holding them for years. Has consistently argued that the market overreacts to short-term problems and undervalues franchises with durable competitive advantages.

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.

Bill Nygren

Oakmark Funds (lead portfolio manager), Harris Associates (partner)

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.

Bill Nygren

CFA charterholder. MBA from the University of Wisconsin-Madison.

Undergraduate degree from the University of Minnesota. Has spent his entire career at Harris Associates — over 40 years at one firm.