📈 How Financial Markets Work

What you’ll learn

1. The Question a Market AnswersExplain what question a market exists to answer and why a price is best understood as the state of an argument rather than a fact.What a company is worth depends on an unknowable future, so there is no true value waiting to be discovered — yet a number is needed for anyone to trade. A market resolves this by making participants back their opinions with their own money, so the resulting price is the balance point of conviction weighted by cash. Every institution in the course — exchange, order book, market maker, clearing house, index — exists to make that argument cheaper, faster or safer to conduct. This course is education, not financial advice.
2. What Is Actually Being TradedDefine shares and bonds precisely as positions in a queue of claims, and show how that framing explains the wider range of instruments.A share is not ownership of physical assets but a residual claim — a right to whatever remains after suppliers, staff, tax and lenders are paid — together with a vote. A bond is a promise of fixed payments with a place ahead of shareholders in the queue, capping the upside in exchange for priority. The distinction is not 'safe versus risky' but a position in a queue and the trade that goes with it, and preferred shares, senior and subordinated debt and government bonds are all variations on the same structure.
3. Where the Money Actually GoesDistinguish primary from secondary markets and explain why trading that funds nothing is nevertheless what makes funding possible.Buying shares on an exchange sends money to the seller, not the company: only the primary market — an IPO or new issue — actually delivers capital to a business, and it is rare. The secondary market is almost all trading and funds nothing directly, but its product is liquidity, the ability to change your mind at a fair price. Because investors know they can exit later they will pay far more at issue, so the second-hand market converts permanent commitment by a company into temporary commitment by individuals, and its prices are what any future issue is priced against.
4. The Order Book: Where a Price Is BornExplain the order book, the limit/market order distinction, and how execution against resting orders produces the price.There is no stored price and nobody sets one: an order book is two sorted lists of what buyers will pay and what sellers will take, and the ticker merely records the last time two entries touched. A limit order controls price but not timing and adds liquidity to the book; a market order controls timing but not price and consumes it, so every trade pairs a patient side with an impatient one. A large market order walks the book through successively worse levels — getting a worse price precisely because it demanded immediacy — and the exchange itself is only a sorting machine ranking by price then time.
5. Liquidity and the People Who Sell ItExplain why liquidity must be supplied, what a market maker risks, and what the bid-ask spread is actually measuring.Buyers and sellers exist but rarely arrive at the same instant, so a market maker bridges that gap in time by quoting both sides and becoming the counterparty when the other side is absent — compensated by the spread. The spread prices two distinct risks: inventory risk, from holding unwanted stock until a buyer appears, and adverse selection, the chance that the counterparty knows more than the market maker does. Because market makers are profit-seeking firms with limited obligations to quote, liquidity is a service that can be withdrawn, and it is thinnest exactly when it is most wanted.
6. Who Is on the Other SideIdentify the main categories of market participant and explain why most trading volume reflects constraints rather than opinions.'The market' is not a crowd of similar people but a set of participants with incompatible horizons and constraints: retail investors, pension funds and insurers driven by liabilities and mandates, funds transmitting their holders' flows, hedge funds, dealers, corporations buying back stock, and high-frequency traders. Market makers, HFTs and index funds transact in enormous volume while holding no view about any company at all. Because the order book cannot distinguish a forced seller from a convinced one, much of what looks like the market forming a judgement is in fact somebody complying with a rule.
7. An Index Is a Number, Not a ThingExplain what an index actually measures, contrast price- and capitalisation-weighting, and show how index membership decisions move markets.An index is an arithmetic recipe rather than a thing: price-weighted indices such as the Dow and Nikkei give influence according to share price, which is arbitrary enough that a stock split halves a company's influence without anything changing. Capitalisation-weighting, used by the S&P 500 and FTSE 100, is defensible because it approximates aggregate holdings, but it lets a handful of the largest members move the whole number. Membership is decided by committees applying criteria that involve judgement, and because trillions track indices, inclusion forces opinion-free buying — so the thermometer now moves the temperature.
8. Active and Passive: A Live ArgumentPresent the active-versus-passive dispute fairly — the arithmetic and evidence on each side — without adjudicating it.The passive case rests on Sharpe's identity, that active dollars collectively are the market so the average one must trail it after costs, reinforced by long-running scorecards such as SPIVA and by survivorship bias in surviving records. The active case replies that the identity constrains the average rather than any individual, that indexing free-rides on the price discovery it declines to perform, that cap-weighted indexing is itself an active momentum-flavoured bet, and that efficiency evidence is weakest in thinly-covered corners. Both sides have real evidence and serious economists, the dispute is live, and this course deliberately declines to settle it.
9. The Plumbing Nobody SeesExplain clearing and settlement — novation, margin, netting and the default waterfall — and why this infrastructure is where crises actually occur.A filled order creates an obligation rather than a shareholding, with the actual exchange occurring at settlement — T+1 in US markets since the SEC's 2024 move from T+2 — and the gap between agreeing and completing is where counterparty risk lives. Because anonymous matching means you never chose your counterparty, a clearing house novates every trade, becoming buyer to the seller and seller to the buyer, protected by margin, a default fund and a loss waterfall shared by surviving members. Netting collapses millions of obligations into a few net movements, and this unglamorous plumbing is precisely what makes it safe to argue with strangers at scale.
10. What Markets Do BadlyAssess honestly what markets do well and what they were never designed to do, drawing the course's mechanisms together into an account of how markets seize up.A price is the state of an argument, and crowds betting real money can be collectively wrong for years — the South Sea Bubble, the late-1990s technology boom and 2008 were not failures to compute but arguments that were losing. The course's caveats compound rather than fail independently: liquidity is a withdrawable service, most volume carries no view, indices are committee recipes, and the plumbing is the fragile part, so in a panic each mechanism amplifies the others into a spiral that dwarfs the triggering news. Markets genuinely aggregate dispersed information, allocate capital and transfer risk, but they do not determine fairness, do not price what is not traded, are not democratic, and cannot be right about an unknowable future.

Questions this course answers

Grounded in trusted sources

• Harris, L., Trading and Exchanges: Market Microstructure for Practitioners (Oxford University Press, 2003)
• Hasbrouck, J., Empirical Market Microstructure (Oxford University Press, 2007)
• O'Hara, M., Market Microstructure Theory (Blackwell, 1995)
• Brealey, R., Myers, S. & Allen, F., Principles of Corporate Finance (McGraw-Hill)
• Sharpe, W. F., 'The Arithmetic of Active Management', Financial Analysts Journal 47(1), 1991
• Grossman, S. J. & Stiglitz, J. E., 'On the Impossibility of Informationally Efficient Markets', American Economic Review, 1980
• S&P Dow Jones Indices — Index Mathematics Methodology
• S&P Dow Jones Indices — SPIVA Scorecards

Every Wunder lesson is built from real, reputable sources — never invented.

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