Charlie Munger

Munger's whole thing is mental models. The idea is simple: instead of being an expert in one field, you learn the core concepts from as many different fields as possible — psychology, biology, physics, economics, history — and then use that whole toolkit to think about problems.

He calls it a latticework of mental models. It sounds like a self-help concept.

It's actually how he consistently made better decisions than almost everyone around him. On investing, he pushed Buffett away from his old mentor's approach — which was basically "find dirt-cheap companies and flip them fast" — toward something more durable: find the best businesses in the world and hold them forever.

The key word he uses is moat. A business so dominant that competitors can't touch it.

Think Coca-Cola. He was also deeply influenced by psychology, particularly the ways humans reliably fool themselves.

He gave a famous talk called "The Psychology of Human Misjudgment" listing 25 ways our brains get things wrong. Reading it once will change how you make decisions.

Benjamin Graham

He treated stocks as ownership stakes in real businesses — not tickets in a lottery. Before Graham, most investment advice was a mix of tips, rumors, and gut feeling.

He brought math to it. His core concept was intrinsic value — a calculation of what a business is actually worth based on its current earnings, assets, and finances.

If the market price is significantly below that number, you buy. The gap between price and value is what he called the margin of safety: the most important concept he ever introduced.

The bigger the margin of safety, the less damage an error in your analysis can do.

He also invented the allegory of Mr. Market — an imaginary business partner who shows up every day offering to buy or sell your shares at whatever price his mood dictates.

When he's euphoric, prices are too high. When he's depressed, prices are too low.

Your job is to exploit his mood swings, not follow them. This was 1949.

It's still the clearest explanation of how to think about market volatility that anyone has ever written.

Charlie Munger

Invert. Always invert.

That's his most famous rule — borrowed from the mathematician Jacobi. Instead of asking "how do I succeed?" ask "what would guarantee failure, and then avoid those things." It sounds obvious.

Almost nobody actually does it. He believes the secret to a good life and good investing is the same: figure out what you want to avoid, avoid it relentlessly, and most good things follow.

On wealth: getting rich isn't the hard part — keeping it is. Most people blow up by using borrowed money, getting greedy at the top, or panicking at the bottom.

Don't do those things. On decisions: only make the big bet when you're very sure.

Be patient for a long time, then move fast when the opportunity is obvious.

Benjamin Graham

Three ideas define him. First: the margin of safety.

Always buy with a meaningful cushion between what you pay and what the thing is actually worth. If you're right, you do very well.

If you're wrong, you don't get wiped out. Second: Mr.

Market is your servant, not your master. The market's daily mood is irrelevant to whether your underlying analysis is correct.

Ignore the noise. Third: an investment operation is one which, upon thorough analysis, promises safety of principal and an adequate return.

Everything else is speculation. He was blunt about this distinction.

Most of what people called investing in his era — and honestly in most eras — was speculation dressed up in confident language.

Charlie Munger

Munger's approach to risk: don't take risks you don't understand, and don't take risks you don't need to. He kept things simple.

He concentrated into a small number of businesses he understood deeply. He never used borrowed money.

He kept large cash reserves. His view on diversification was almost the opposite of what most financial advisors tell you — he thought spreading money across 50 stocks was an admission that you hadn't done enough homework.

If you've done the work, you concentrate. If you haven't, maybe don't invest at all.

Benjamin Graham

He was conservative to the point that contemporaries sometimes called it excessive caution. He wanted a margin of safety large enough to survive being significantly wrong in his own analysis.

He preferred businesses with consistent earnings histories, strong balance sheets, and low debt. He did not trust projections about future growth — he trusted current, auditable numbers.

If a company looked cheap based on what it had already proven it could earn, he was interested. If it required optimistic future projections to justify the price, he was not.

He believed overconfidence in predictions was the primary source of investment losses, full stop.

Charlie Munger

Munger lived in the same house in Los Angeles for most of his adult life. He was famously frugal — not in a miserable way, but in a "I genuinely don't care about most things money buys" way.

He flew commercial until fairly recently. He read obsessively.

He described himself as a book with legs. His children joked that he was more interesting to talk to than almost anyone alive, but would only engage on topics he found intellectually stimulating.

He donated massively to education — hundreds of millions to Harvard Law School, the University of Michigan, and other institutions, often with very specific conditions attached. He designed buildings as a hobby and funded their construction himself.

He died at 99 worth around $2.6 billion — extraordinary by any measure, and somehow modest given he sat next to one of the richest men in history for 45 years.

Benjamin Graham

He was genuinely modest about money. He found the intellectual puzzle of valuation more interesting than the wealth it could produce.

He retired to California on a comfortable but not extravagant income. He taught at Columbia for nearly three decades for standard academic pay.

His students — particularly Warren Buffett — went on to make orders of magnitude more money than Graham himself did by applying his methods. He spent his later years writing, revising his ideas, and reportedly reading Latin and Greek for pleasure.

He was described by people who knew him as charming, witty, and multilingual.

Charlie Munger

See's Candies. In 1972, Munger convinced a reluctant Buffett to pay what seemed like an expensive price — $25 million — for a California candy company.

Buffett thought it was too much. Munger held firm.

See's has since generated over $2 billion in profit for Berkshire, basically funding dozens of other acquisitions. It also taught Buffett the single most important lesson of his career: paying a fair price for a great business beats getting a cheap price for a mediocre one.

That one deal changed the entire direction of Berkshire Hathaway.

Benjamin Graham

GEICO. In 1948, Graham-Newman invested $720,000 in GEICO when it was a small, obscure government employees insurance operation.

This was roughly half the fund's total assets — a concentration level Graham himself had written against. The position grew to be worth tens of millions before he died.

Beyond the financial return, the GEICO investment influenced Warren Buffett to study the company intensively, and Buffett eventually acquired all of GEICO for Berkshire Hathaway in 1996. One investment produced ripples across a century of finance.

Charlie Munger

Munger is famous for avoiding mistakes more than for making spectacular wins — his whole philosophy is about not doing stupid things. But he's admitted to a few.

He said Berkshire was too slow to move into BYD, China's electric vehicle company, despite knowing it was exceptional for years before they finally bought in. He also held too much Wesco Financial for too long when the money could have been put to better use elsewhere.

His most honest self-criticism: he wished he had moved faster when the evidence was already clear. For a man who spent his career warning others about psychological biases, he wasn't immune to them.

Benjamin Graham

The 1929 crash. He had spent years writing about valuation and the concept of cheap stocks.

He still got caught up in the late 1920s bull market excitement and didn't apply his own principles rigorously enough. He lost significant money.

He later described it with uncommon honesty — not blaming bad luck, not glossing over it, just saying he failed to follow his own rules. The crash was the crucible.

Security Analysis came out in 1934. The Intelligent Investor followed in 1949.

Both books came directly from working through what went wrong and why. The mistake produced the framework that generated more investment wealth than almost any other set of ideas in history.

Charlie Munger

Charlie Munger grew up in Omaha — same city as Buffett, but they didn't know each other yet. His father was a lawyer.

So was his grandfather. Charlie became one too, but he was clearly more interested in figuring out how the world worked than in courtrooms.

He studied math at the University of Michigan, got drafted into World War II, trained as a meteorologist, and somehow ended up at Harvard Law School without ever finishing an undergraduate degree. Harvard took him anyway.

He graduated in 1948 and moved to California to practice law. He was good at it.

He was also quietly building a real estate business on the side that made him more money than law ever did. He and Buffett met at a dinner in Omaha in 1959.

Munger was 35. Buffett was 28.

By the end of the night, Buffett was trying to convince Munger to go into investing full time. It took about a decade.

Munger ran his own investment partnership from 1962 to 1975 — returned 24% annually while the market did 6.4%. Then he fully merged his career with Buffett's at Berkshire, where he stayed until his death in 2023.

Benjamin Graham

Benjamin Graham was born Benjamin Grossbaum in London in 1894. His family moved to New York when he was a year old.

His father died when Graham was nine. His family lost most of their savings in the 1907 financial panic.

He grew up with a serious understanding of what it actually meant to lose money.

He graduated from Columbia University in 1914 at age 20, second in his class. The university offered him teaching positions in three departments — English, philosophy, and mathematics.

He chose Wall Street instead. He started the Graham-Newman Corporation in 1926, which functioned as a hedge fund before anyone used that term.

He lost heavily in the 1929 crash — which he later admitted meant he hadn't been following his own principles rigorously enough. He spent the 1930s rebuilding, writing, and thinking.

He taught at Columbia Business School from 1928 to 1956. His greatest student was Warren Buffett, who took his class in 1950 and called it the most important educational experience of his life.

Graham retired to California in 1956 and spent his last years revising his investment philosophy and living simply. He died in Aix-en-Provence, France, in 1976.

Charlie Munger

Munger's main stage was Berkshire Hathaway, where he served as Vice Chairman from 1978 until he died. His role was hard to define on paper — he didn't run a fund or manage a portfolio.

What he actually did was talk to Buffett. That was worth a trillion dollars.

Before Berkshire, he ran his own investment partnership from 1962 to 1975 that crushed the market. He also controlled Wesco Financial, a small insurance and financial company he ran as a personal Berkshire subsidiary from 1973 to 2011, until Berkshire fully absorbed it.

Outside finance, he was obsessed with architecture — he personally designed several buildings, including a dormitory at the University of Michigan that his own architecture school rejected for violating design principles. He funded it anyway.

Benjamin Graham

Graham-Newman Corporation, which he co-founded and ran from 1926 to 1956, delivered roughly 20% annual returns over that period — outstanding for any era, remarkable given it spanned the Great Depression. His single best investment was GEICO.

In 1948, the fund put approximately $720,000 into GEICO — about half the fund's total assets at the time. That was a violation of his own concentration rules, which tells you how strongly he felt about it.

When the fund dissolved in 1956, GEICO shares were distributed to investors. Graham held his personally.

By the 1970s they were worth millions. Warren Buffett later bought the entire company for Berkshire Hathaway.

The ripple effect of that one position is impossible to fully calculate.

Charlie Munger

University of Michigan, mathematics — left for World War II without graduating. US Army Air Corps, meteorology training.

Harvard Law School, JD 1948 — admitted without an undergraduate degree, which Harvard is apparently capable of when it wants to be.

Benjamin Graham

Columbia University, class of 1914. Graduated at age 20, second in his class.

Offered teaching positions in English, philosophy, and mathematics — chose Wall Street. Taught at Columbia Business School from 1928 to 1956.

Also lectured at UCLA in retirement. His formal education ended at Columbia but his actual education never stopped.