Money math, shown in full.
Most money writing tells you the conclusion. This one shows the arithmetic that got there, so you can check it — and disagree with it.
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Total-Market Funds and S&P 500 Funds: The Actual Difference
One holds a few hundred large companies, the other holds thousands. In practice they behave more alike than that suggests, and the reason explains most of what people get wrong about diversification.
Investing3 min read
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All articlesHow Many Funds a Portfolio Actually Needs
Adding a fifth fund usually changes a portfolio less than people expect. The reason is structural, and you can check it on your own holdings in about two minutes.
Investing3 min read
What a Credit Card Annual Fee Actually Has to Earn Back
An annual fee is not a cost or a bargain on its own — it is a break-even problem. Here is the arithmetic, and the three places it usually goes wrong.
Credit Cards3 min read
Compounding Is Back-Loaded, and That Changes What You Should Worry About
Most of the growth in a long investment horizon arrives at the end. Understanding why explains both why starting early matters and why the early years feel like nothing is happening.
Investing3 min read