The Stock Market
The equity market: how a share is priced and what valuation predicts, the indices and the concentration inside them, with seven companies at a third of the S&P 500, passive investing, the plumbing of trading, buybacks, the record listings from SpaceX to Anthropic, retail trading and options, the world's markets, rates, the crashes from 1929 to the 2026 war correction, the AI question, and what a century of evidence says about investing. Written as of October 2026, when earnings growing by a third had brought the forward multiple back to its ten-year average while the cyclically adjusted price-earnings ratio stood second only to 1999-2000. Where investors argue, from today's multiple and passive investing to payment for order flow, buybacks, owning abroad, and the AI build-out, each side makes its case before the evidence. Opens with a market snapshot from one day's close, and its worked examples run on October's numbers, from Apple's price read as an expectation to what a rise in rates does to the multiple.