LearningLibrary

subject

Investing

How markets, portfolios, and risk actually behave. Educational rather than advisory: the lessons describe what is, not what to do.

13 lessons in investing

Level:
intro college

Active and Passive Management: The Long-Running Debate

In 2007, Warren Buffett offered a wager: over the next ten years, a plain S&P 500 index fund would beat any basket of hedge funds a professional could assemble, after fees.

4 min · comparison

intro college

How Compound Interest Works Over Long Horizons

Imagine two siblings, both earning the same modest salary. One begins setting aside a fixed sum each year at age twenty-five and stops at thirty-five. The other waits until thirty-five and contributes…

4 min · foundation

9th grade

How Insurance Pools Risk

Imagine a thousand families on a block. Every year, by bad luck, about three of those houses catch fire. Nobody knows which three. If your house is one of them, the loss is ruinous — maybe half a mill…

3 min · deepening

9th grade

Saving and Investing: Two Different Things Your Money Can Do

Imagine you have eighty dollars in a shoebox under your bed. The money is safe in the ordinary sense — no one is going to steal it tonight — but it is also doing nothing. A year from now, you will sti…

3 min · comparison

intro college

What a Stock Actually Represents

When most people picture a stock, they picture a flickering price on a screen.

3 min · foundation

intro college

What an Index Fund Tracks and Why It's Cheap

Imagine a librarian whose only job is to keep the shelves arranged in exactly the same order as a master catalog printed somewhere else.

4 min · deepening

9th grade

What Happens When You Put Money in a Savings Account

Picture walking into a bank with two crisp twenty-dollar bills and handing them to a teller.

3 min · foundation

9th grade

What Inflation Actually Is

In 1970, a movie ticket in the United States cost about a dollar and a half.

3 min · foundation

intro college

Why Bond Prices Move Opposite to Interest Rates

Imagine you bought a bond last month for $1,000. It promises to pay you $40 every year for ten years and then return your $1,000 at the end. A week later, your neighbor walks into the same brokerage a…

4 min · foundation

intro college

Why Markets Are Hard to Beat: The Efficient Markets Hypothesis

Imagine a hundred-dollar bill lying on a busy sidewalk. An economist walks past without bending down. Asked why, she answers: if it were really there, someone would have picked it up already. The joke…

4 min · synthesis

9th grade

Why Two Stocks at the Same Price Aren't Worth the Same Amount

Imagine two pizzas sitting on a counter. Both cost twelve dollars. One has been cut into eight slices; the other has been cut into a hundred. If someone offers you a slice of each for the same price, …

3 min · foundation

9th grade

Why Volatility Is Not the Same as Risk

Picture two stocks side by side on a chart. The first one zigzags wildly every week — up 8%, down 6%, up 4%, down 9%. The second one drifts along a nearly flat line, barely moving. Most people, lookin…

3 min · deepening

intro college

Why Volatility Is Not the Same as Risk

Imagine two assets. The first drifts upward in a jagged line, gaining ten percent some months and losing eight percent in others, but ending the decade at three times its starting value. The second si…

4 min · deepening