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What a stock market heatmap shows, why tile sizes are square-rooted, why the colours rescale with the time window, and what the map cannot tell you.

How to read 13F filings: the 45-day reporting lag, what the form leaves out including short positions, and what fund holdings data can and cannot tell you.

What the STOCK Act requires, why the disclosed amounts are brackets rather than figures, the 45-day reporting delay, and what a filing does not prove.

Why the EPS figure on an earnings calendar is a consensus estimate and never a result, why scheduled dates move, and what an ex-dividend date actually means.

How the price-to-earnings ratio is built, the difference between trailing and forward P/E, and the situations where the number stops meaning anything.

What a DCF actually calculates, why the terminal value usually dominates the answer, and why small changes to the discount rate move the result so much.

Market cap is share price times shares outstanding, and both halves are harder than they look. Share classes, ADRs, free float, and why heatmap tiles are square-rooted.

Why enterprise value is the right numerator when debt matters, what EBITDA deliberately ignores, and where the multiple flatters capital-hungry businesses.

How the price-to-book ratio works, why it still matters for banks and insurers, why it stopped working for most other companies, and the traps in the per-share figure.

Why free cash flow and net income diverge, what stock-based compensation does to the figure, and how to read a company that is profitable but consumes cash.

What earnings per share measures, why basic and diluted differ, how buybacks raise EPS without the business improving, and the share-class traps in the denominator.

How ROE is calculated, why the same figure can describe a great business or a heavily borrowed one, and why buybacks and negative equity break it entirely.

What each profit margin measures, why gross margin says most about pricing power, why net margin is the noisiest, and why some companies have no gross margin at all.

What dividend yield measures, why a rising yield is usually a falling share price, how payout ratios indicate sustainability, and what the ex-dividend date does.

How the 14-period relative strength index is calculated, what overbought and oversold actually mean, and why the indicator fails in exactly the conditions people reach for it.

What the 50 and 200-day moving averages do, why every moving average lags by construction, what VWAP measures, and how MACD is built out of them.