The Field Guide
Finance, with the arithmetic left in.
Every concept here comes with a worked number. No vibes.
Most explanations of compounding tell you it's powerful and stop. That's useless; you already knew it was powerful. What you need is the number: how much, by when, and which part of the curve does the work. So each entry below states the idea in one line, explains why it matters, and then shows the actual math.
This is a reference, not a course. Skim the contents, take what you need, and leave.
Sections
94 entries-
The FIRE math
Compounding, savings rates, and what a portfolio has to be worth before it pays you.
Compounding, savings rate, your fi number & the 4% rule, real vs nominal returns, the rule of 72, sequence of returns risk, inflation, basis point, opportunity cost.
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Investing mechanics
The frictions that decide how much of a return you actually keep.
Expense ratios, dollar-cost averaging vs lump sum, rebalancing, asset location, tax drag, turnover, treasury bills, duration, tax-equivalent yield, fdic insurance, money market funds, liquidity, capital gains, short and long, marginal rate, cost basis, restricted stock units, dividends, qualified dividends, the ex-dividend date.
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Reading a company
The vocabulary the research reports use, and what each number can and cannot tell you.
The p/e ratio, free cash flow vs net income, buybacks and eps, shareholder yield, payout ratio, tangible book value, return on tangible common equity, goodwill, impairment, working capital, economic moat.
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Capital and the balance sheet
Where the money comes from, what it costs, and whether the business survives long enough for you to be right.
Return on invested capital, cost of capital, reinvestment rate, ebitda, net debt and covenants, operating leverage, control premium, synergies, covenants, stock-based compensation.
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Valuation and what a price implies
Every price is a forecast. These are the tools for reading the forecast back out of it.
Enterprise value, normalized earnings, reverse dcf, dilution, margin of safety, terminal value, earnings yield, cost of equity, sum of the parts.
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Risk and what it costs
Risk is not one thing. These are the six ways it shows up, and which of them you are paid to bear.
Volatility, volatility drag, beta, drawdown, diversification, correlation, path dependency, concentration risk.
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Accounts and the tax code
Three ways the government can tax the same dollar, and the rules that decide which one applies.
Tax-deferred accounts, roth accounts, taxable brokerage, health savings account, required minimum distributions, roth conversion, 529 plans, qualified expenses, full retirement age, delayed retirement credits, annuities.
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Banks and lenders
A lender is a balance sheet with a spread on it. These are the six numbers that say whether the spread is worth owning.
Net interest margin, net charge-offs, provisions and the allowance, cet1 and capital ratios, book value and tangible book value, justified price to tangible book.
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Marketplaces and platforms
Platforms report one very large number that is not theirs and one small one that is. Telling them apart is most of the work.
Gross bookings and volume, take rate, transaction margin, the rule of 40, cohort economics.
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Insurance and protection
The same vocabulary read two ways: as a business you might own, and as a policy you have probably bought the wrong version of.
Float, combined ratio, premiums written and premiums earned, own-occupation coverage, elimination period, income replacement ratio.
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