The players and what they actually do

After this lesson you can name the main participants in a stock market, what each one wants, and which constraint each one can't escape.

The table you're joining

When your buy order reaches the market, whoever sells to you comes from a fairly short list of characters. They differ enormously in size and in what they're trying to do, and the differences are worth learning properly, because much later (School IV) your entire method comes down to reading the behaviour of the biggest ones.

Retail traders — you. Individuals trading their own money. You answer to nobody, so you can sit in cash for a year without a client firing you, and your orders are small enough to get into or out of almost any stock in seconds without moving its price. The costs you pay are proportionally higher than a professional's, and information reaches you late. Nobody checks your work either, which is a large part of why School II exists.

Market makers — firms that continuously quote both a bid and an ask in a stock. They make their money on the spread, collected thousands of times a day, and what they're trying to avoid is ending up holding a large position by accident, so they adjust their quotes constantly to stay roughly flat. They're the reason you can sell at 14:47 on an ordinary Tuesday and be done in seconds, because somebody is always quoting.

High-frequency traders — specialists in speed, holding positions for seconds or less and competing for tiny edges millions of times over. Their net effect on you is spreads far cheaper than retail traders paid a generation ago. You will also never win a race measured in microseconds, so speed is one thing you can cross off the list when you go looking for your own edge.

Mutual funds and pension funds — the giants. They manage the retirement money of millions of people and get measured against a benchmark (course 7). The constraint that matters most to this Academy is their size: a fund that wants a position has to build it over days or weeks of steady buying, and there's no quiet way to do that. All that drawn-out accumulation leaves marks in price and volume, and School IV is largely the craft of noticing them.

Hedge funds and prop desks — professional risk-takers with flexible mandates. They can be long or short, levered or not. As a group they're too varied to say much about, except that the disciplined ones are running the same risk arithmetic School II teaches you.

Central banks — they'll never trade your stock, but they set the price of money itself: interest rates, and the supply of liquidity underneath everything. When that changes, every asset gets repriced around it. School IX covers the mechanism, and School IV's regime lessons are the practical response.

The point of the roster

The constraints are the useful part. A giant fund can't hide its size and a market maker can't sit on inventory, and neither of them gets to choose otherwise. You have constraints of your own, the costs and the information lag above. You also have something most professionals don't, which is permission to do nothing at all, in full cash, for as long as you like, with nobody calling to ask why.

Check yourself

1. Why can you sell a liquid stock within seconds at 11:03 on an ordinary day? (A market maker is quoting both sides to earn the spread. Your counterparty is doing business; it doesn't need to share your opinion.)
2. Which player's constraint creates the trace School IV teaches you to read? (The big funds'. Their size forces slow, visible accumulation.)
3. Name two freedoms a retail trader has that a pension-fund manager doesn't. (Sitting fully in cash indefinitely; entering or exiting instantly without moving the price.)

The idea this lesson installs

Every player at the table has a constraint, and the biggest players can't hide theirs.

Next: Course 4 — "What a stock is."