CHAPTER 4 · Adult Education
Know what moves the price
Explain how discount rates affect bonds and equity valuations without treating them as identical.
Michael Lewis, Liar’s Poker · Chapter 4. Original paraphrase and analysis; not the book text.
The idea beneath the story
The training programme introduces Lewis to the firm’s product hierarchies and to people who explain markets in very different ways. Bond trading occupies a central position in the story. Equities can appear comparatively unfashionable inside this particular firm, despite their prominence in the public imagination. This contrast is a useful warning: an institution’s internal prestige ranking is not a map of all the important opportunities in finance.
A basic bond lesson is that a fixed future payment becomes less valuable today when the required discount rate rises, other things equal. Consider a hypothetical zero-coupon bond paying £100 in five years. At a 5% annual yield its value is 100 divided by 1.05 to the fifth power, approximately £78.35. At 7% it is about £71.30. The issuer has not missed a payment in this example. The price change arises because the opportunity cost of waiting has changed.
Stocks also depend on future cash flows, but they are not fixed-payment bonds. Sales, margins, reinvestment, taxes, debt and the number of shares can all change. A rise in interest rates may increase the discount rate while also changing demand or financing costs. In some businesses it can raise income on assets. The direction and scale of the net effect require a business-specific explanation. Saying that a company is a long-duration stock can be a useful shorthand, but it is not a substitute for a cash-flow model.
Duration summarises sensitivity to a small yield change. A rough approximation is percentage price change equals minus modified duration times the yield change expressed as a decimal. A duration of five and a one-percentage-point rise suggest a decline of about 5%. This is a local approximation, not an exact promise. Large moves, changing credit spreads and embedded options can make the answer different. Mortgage borrowers’ ability to repay early makes this especially important in the next chapters.
The stock investor’s second task is to connect asset prices to the company’s liabilities. A bank can own securities with low credit risk and still have a dangerous balance sheet if customers can demand cash much sooner than the assets mature. Holding an asset to maturity is possible only if funding remains available. Accounting classification does not create that funding. A loss that is unrealised for accounting purposes can still matter to a buyer deciding what the bank’s equity is worth.
Hypothetical worked example: a firm owns £100 million of assets financed by £90 million of liabilities and £10 million of equity. If the economic value of the assets falls by £6 million and the liabilities are unchanged, equity becomes £4 million. A 6% asset decline has produced a 60% equity decline. This is a simplified mark-to-market balance sheet, not a forecast for a bank. Real analysis must include hedges, other assets, earnings, liability behaviour and applicable accounting.
The SVB case is a later comparison about management, interest-rate exposure and funding concentration. It is not proof that every rise in rates causes a bank failure. A funded investor with a long horizon faces different constraints from an institution with concentrated withdrawable deposits. The point is to ask which clock controls the decision: the asset’s maturity, the next funding renewal or the next wave of withdrawals.
A useful learning habit is to explain a price move twice. First describe the security: what cash flows, what required return, what optionality? Then describe the holder: how financed, how much equity, what demands for cash? If the two explanations are merged, it becomes easy to call a good-quality asset a safe investment even when it sits inside a fragile structure. Understanding the instrument is necessary; understanding the balance sheet makes the lesson usable.
Silicon Valley Bank: the asset and the funding
The SVB comparison separates the quality of a security from the resilience of the institution holding it. A shareholder owns the residual balance sheet, not an isolated bond. This case is shared with related chapters.
Documented sequence. Silicon Valley Bank failed in March 2023. The Federal Reserve’s subsequent review identified failures by management and the board to manage risk, alongside shortcomings in supervision. Rapid growth, concentrated funding, interest-rate exposure and a fast-moving run were central to its explanation. This is the regulator’s retrospective review, which also criticised its own supervisory approach. It is not a claim that all banks with securities portfolios face the same outcome.
Federal Reserve · SVB review, April 2023 · Checked 10 October 2026
Original analysis: one balance sheet, two clocks. An asset can promise payment years from now while a liability can be withdrawn today. The gap does not automatically cause failure; banking normally involves maturity transformation. It becomes dangerous when the cash available, the ability to borrow and the assets that can be sold are insufficient for the demand. The analyst needs both the asset’s economic value and the institution’s capacity to realise that value on time.
A high-quality bond has low expected credit loss relative to a weaker promise, but its market price can still decline when rates rise. If the holder can wait, the contractual payment may remain valuable. If the holder must sell immediately, the market price matters. The accounting label attached to the security does not determine whether a depositor waits. This is a general balance-sheet explanation, not a reconstruction of every security held by SVB.
Hypothetical worked example. A bank has £10 of cash and £90 of securities funded by £90 of deposits and £10 of equity. Customers request £30. Cash covers £10, leaving £20 to obtain. If securities can be sold for 80% of their carrying amount, the bank must sell £25 of carrying value to raise £20, crystallising a £5 difference. The simplified example ignores borrowing facilities, hedges and other cash flows. It shows why the size of the cash demand and the sale price interact.
Funding concentration adds a separate question. Ten thousand accounts are not necessarily ten thousand independent decisions if customers share an industry, advisers or cash-flow cycle. A balance sheet can look diversified by account count yet face correlated withdrawals. Conversely, a concentrated customer base is not by itself proof of imminent failure. The useful test combines concentration with liquidity, communication, asset sensitivity and available financing.
For stock investors, the distinction between depositors and shareholders is essential. Their claims occupy different positions and may receive different treatment in a resolution. Do not infer that protecting one group preserves the value of another. A bank share is a residual claim whose value depends on assets after liabilities and resolution outcomes. A reassuring statement about customer access to money is not automatically a statement about shareholder recovery.
A common misunderstanding is to reduce the story to either bad bonds or panicky depositors. Such a binary misses management choices and the interaction between asset risk and funding behaviour. Another is to assume that all unrealised losses are irrelevant because a security may eventually repay. They can affect confidence, collateral and the cost of obtaining cash before maturity.
Takeaway. Ask whether a stress scenario joins the asset and liability sides. A useful exercise changes interest rates and withdrawal demands together, then checks executable sources of cash. It should distinguish an accounting loss, an economic loss and an immediate payment shortfall. Those concepts overlap, but they answer different questions about whether an institution can continue operating.
Workshop: read the financed balance sheet
Begin with an identity rather than a forecast: assets are financed by liabilities and equity. The identity is simple; measuring the components is not. Some assets trade frequently, some depend on estimates and some cannot be sold quickly without disrupting the business. Liabilities differ in maturity, security and the conditions that permit acceleration. Equity absorbs the residual economic change, but accounting equity and a market valuation of equity need not coincide. Before using a ratio, state which version of each component it contains and what question that ratio can answer.
A company with £100 of assets and £20 of equity has five times as many assets as equity. If liabilities remain £80 and asset value falls by £10, the residual equity becomes £10. The asset decline is 10%, while the equity decline is 50%. This simple calculation omits taxes, hedges and changes in liabilities. Its purpose is to expose the denominator. A small percentage move in a large asset base can be a large percentage move in a thin residual claim. Calling the assets diversified does not change this arithmetic.
Now introduce cash timing. Suppose the same company owes £15 next week but has only £5 of immediately available cash. It needs another £10 through collections, borrowing, new equity or asset sales. Having positive net assets does not specify which source will arrive in time. A valuable factory cannot necessarily be converted into cash by Friday. Conversely, a temporary cash shortfall may be solvable with committed financing even when the current cash balance looks low. Solvency and liquidity are related, but one is not a complete substitute for the other.
Build a maturity ladder rather than a single debt total. List obligations by the dates on which cash can be demanded, including conditions that bring those dates forward. For a margin-financed position, the effective demand can arise before the nominal final maturity. For a revolving facility, availability may depend on covenants or the borrowing base. A stress scenario should identify which promises remain usable under the same conditions that create the cash need. Counting a facility as protection while ignoring the clause that could restrict it during stress creates circular reassurance.
A hypothetical collateral example makes the interaction visible. A lender advances £80 against an asset worth £100, requiring a 20% haircut. If the asset falls to £90 and the haircut rises to 30%, permitted borrowing becomes £63. The borrower must repay £17 or supply acceptable additional collateral, even though the asset price fell only £10. The haircut change magnifies the cash demand. This is an invented contractual example, not a universal margin rule. The actual agreement determines what collateral qualifies, how it is valued and when payment is due.
The next question is whether risks move together. A company may model lower asset prices in one scenario and higher funding costs in another, yet encounter both simultaneously. Customer withdrawals may also accelerate when the firm announces a loss. Correlation is not fixed merely because a spreadsheet uses a fixed number. Write a causal story about the stress: which event affects the asset, which affects the liability and why might they reinforce each other? This does not require predicting the exact next crisis. It requires avoiding an assumption that each problem politely arrives alone.
Distinguish a hedge from a complete solution. An interest-rate hedge may offset some market-value sensitivity while leaving basis risk, collateral demands, counterparty exposure or funding concentration. A hedge can also introduce its own cash timing. The relevant question is the combined position under the stated scenario, not whether a line in the report says hedged. At the same time, do not assume hedges are useless because they are imperfect. A partial hedge can materially reduce risk if its limitations and operating requirements are understood and supported.
For an ordinary company, debt-funded growth deserves a per-share bridge. Start with the operating benefit expected from the investment. Subtract financing costs, additional maintenance needs and the consequences of issuing new shares. Then test a weaker operating result and a more expensive refinancing. A larger company can have lower value per existing share if too much is paid or financing is fragile. The claim that a deal is earnings-accretive is not a complete valuation argument: accounting earnings can rise while the economic return on the capital committed remains disappointing.
A good stress table includes actions, not only losses. If equity falls below a chosen threshold, what can management realistically do? Selling assets can crystallise losses, raising equity can dilute existing owners and reducing lending can damage future revenue. Those responses may still be the best available choices. State their costs instead of treating them as frictionless rescue buttons. A plan that depends on selling the least liquid asset at yesterday’s price during a market-wide shock should be marked as an assumption needing evidence, not a guaranteed source of funds.
Finally, connect the analysis to decision size. A position that is tolerable without borrowing may be intolerable with a short financing deadline. A favourable long-run estimate does not make every capital structure sensible. The workshop does not determine an appropriate personal portfolio or offer a leverage target. It teaches a sequence: identify the claim, trace the cash demands, combine stresses and test the available responses. Confidence becomes more useful when it is attached to those constraints. Without them, a persuasive valuation is only one part of an unfinished investment argument.
A final boundary is the distinction between a company’s resilience and an investor’s financing. An unleveraged company can still be held in a highly leveraged account. Conversely, a conservatively financed shareholder can own a fragile financial institution. Analyse both layers when they are relevant. The company’s cash flow does not automatically meet the investor’s margin demand, and the investor’s patience does not repair the company’s refinancing problem. This separation also clarifies why the same share can create different practical risks for different holders. Our examples examine mechanisms, not personal suitability. A complete account names the layer at which the obligation arises and the party that can enforce it. Otherwise, words such as long term and high quality can slide between meanings, offering comfort without answering the actual cash question.
Decision exercise (hypothetical)
A bank owns high-quality long-term bonds and relies on a few large depositors. What needs testing?
- Only the bonds’ default probability
Credit quality alone misses timing and funding risk.
- Interest-rate losses and simultaneous withdrawals
Yes. Combine asset sensitivity with the funding clock.
- Whether the bank’s brand is familiar
Familiarity does not measure liquidity.
Recall and self-check
What is duration?
An approximation to price sensitivity to yield changes, subject to assumptions.
Can a bond lose market value without default?
Yes. A higher required yield can lower the present value of unchanged payments.
Reflection
Which funding assumption is hidden in the phrase ‘we can hold it to maturity’?
It assumes no cash demand forces an earlier sale, or that replacement funding is available on workable terms.
Open interactive chapter & notes