How this industry works
Every other page here answers “which tool”. These answer the questions that decide whether the answer is usable at all — what an exchange charges for its own prices, who owns the identifier on a security, what an index licence covers. Reference pages, corrected in place rather than dated, each one cited.
What alternative data actually costs
Satellite counts and card panels are sold by contract, not by price page. What the industry spends, why nobody quotes a number, and what a small buyer gets.
Next to Market DataUpdated
When a trade shows up in the public record
Form 4, Schedule 13D, 13F and congressional reports each run on their own clock. What each contains, how old it is when you see it, and what it never shows.
Next to Insider & 13FUpdated
CUSIP vs ISIN vs FIGI: which identifier to build on
Tickers are free and ambiguous. CUSIP, ISIN and SEDOL are unambiguous and licensed. FIGI, LEI and CIK are unambiguous and free — start there.
Next to Market DataUpdated
Free stock market data, and where the free layer stops
The genuinely free financial data is published by regulators and central banks, not vendors. What that covers, and the first thing you have to pay for.
Next to Market DataUpdated
Historical S&P 500 constituents and survivorship bias
An index's historical membership list is licensed data, not a public fact. What point-in-time constituents cost, and the free route that works going forward.
Next to BacktestingUpdated
Financial MCP servers, and the licence behind them
MCP changes how market data reaches a model, not who may send it. The mechanism from the spec, three exchanges' published AI positions, and what breaks.
Next to MCP & AI AgentsUpdated
Why real-time stock data is so expensive
You are not paying the API vendor, you are paying the exchange — and in US markets the exchange's price list is filed with the SEC and public.
Next to Market DataUpdated
Choosing a database for tick data
A day of US equity quotes is 1.9 billion records. Why row stores fail on it, why the as-of join decides the engine, and how to size before you pick.
Next to Tick StorageUpdated
Where research terminals get their data
Koyfin, TIKR, GuruFocus and Stock Rover all publish who supplies their numbers. What those wholesale licences are, and what they stop a product doing.
Next to FundamentalsUpdated
Who owns the market data industry
The visible brands are terminals. The durable positions sit underneath — exchange data rights, identifiers, index licensing, ratings — mapped from filings.
Next to Market DataUpdated
Why two providers give different returns for the same stock
Adjusted close is computed, not observed. How splits, dividends and spin-offs are folded back through history, and why two correct series disagree.
Next to Market DataUpdated