Chapter 28 — The Financial System

Saving, Investment, and the Loanable Funds Market

Chapters 26 and 27 focused on money, banking, and the Fed's monetary policy. This chapter steps back and looks at the broader financial system: how saving becomes investment, what determines the interest rate, and what happens when government borrowing competes with private borrowing.

The central model is the loanable funds market — a supply-and-demand framework where the "good" being traded is borrowable funds. Savers supply funds (they want to earn interest). Borrowers demand funds (firms investing in capital, households buying homes, governments financing deficits). The real interest rate equilibrates the market.

28.1 The loanable funds model

Supply of loanable funds = saving. Households save part of their income. The higher the real interest rate, the more attractive saving becomes (you earn more on your savings), so the supply curve slopes upward.

Demand for loanable funds = investment + government borrowing. Firms borrow to invest in capital (new factories, equipment, R&D). Households borrow for big purchases (homes, education). The government borrows to finance deficits. The lower the real interest rate, the cheaper it is to borrow, so the demand curve slopes downward.

Equilibrium: the real interest rate adjusts until saving equals borrowing. This is the interest rate that coordinates how much of the economy's output is consumed now versus saved for the future.

The real interest rate = nominal interest rate − inflation rate. The Fisher equation: nominal rate ≈ real rate + expected inflation.

28.2 Government deficits and crowding out

When the government runs a budget deficit, it borrows in the loanable funds market — competing with private borrowers. The additional demand for funds shifts the demand curve rightward, pushing the real interest rate up. The higher rate discourages some private investment (firms find borrowing more expensive). This displacement of private investment by government borrowing is crowding out.

The size of crowding out depends on conditions: - In a normal economy (near full employment): crowding out is significant. Government borrowing competes directly with private investment, and the interest rate rises meaningfully. - In a recession (below full employment, with the zero lower bound): crowding out is small or zero. There is abundant saving (people are scared and saving more) and weak private investment demand (firms don't want to invest during a recession). Government borrowing absorbs slack funds rather than displacing private borrowers. This is the Keynesian argument for deficit spending during recessions. - In an open economy: if foreign saving flows in (attracted by higher U.S. interest rates), the supply of loanable funds increases, partially offsetting the crowding-out effect.

28.3 Financial intermediation

The financial system channels funds from savers to borrowers through two main mechanisms:

Bank-based intermediation: you deposit money in a bank. The bank lends it to a borrower. The bank bears the credit risk, manages the mismatch between your short-term deposit and the borrower's long-term loan, and earns a spread (the difference between the lending rate and the deposit rate). This is the system from Chapter 26.

Market-based intermediation: savers buy financial instruments directly. - Bonds: a loan from the buyer to the issuer. The buyer receives interest payments and the return of principal at maturity. Bonds vary by issuer (government, corporate), maturity (1 month to 30 years), and risk (Treasury bonds are near-riskless; corporate bonds vary). - Stocks (equity): a share of ownership in a firm. The buyer receives dividends (if any) and benefits from appreciation in the stock price. Stocks are riskier than bonds but historically earn higher average returns.

Risk and return: higher risk → higher expected return (the risk premium). A stock that might lose 30% of its value must offer a higher expected return than a Treasury bond that won't lose anything, or no one would hold the stock.

Diversification: spreading investments across many assets reduces risk without reducing expected return (much). If you hold stocks from 500 different companies, a bad quarter for one company barely affects your portfolio. This is the logic behind index funds — and it's one of the most important insights in personal finance.

28.4 The efficient market hypothesis

Efficient market hypothesis (EMH): financial markets incorporate all available information into asset prices. You can't consistently "beat the market" because prices already reflect everything known.

Three forms: - Weak form: past prices can't predict future prices. Technical analysis (chart reading) doesn't work. - Semi-strong form: public information is fully reflected in prices. Fundamental analysis (reading financial statements) doesn't give you an edge over the market. - Strong form: even private (inside) information is reflected in prices. This is the most extreme claim and the least supported.

Evidence: weak and semi-strong forms have substantial empirical support. Most actively managed mutual funds underperform index funds after fees. The average investor would be better off buying a diversified index fund and holding it than trying to pick stocks.

Where EMH breaks down: bubbles (the 2000 tech bubble, the 2006 housing bubble), momentum effects (stocks that have risen recently tend to keep rising for a while), and behavioral anomalies (loss aversion causes investors to sell winners too early and hold losers too long). EMH is a useful approximation, not a universal law.

The practical implication for the reader: if you're saving for retirement, buy a diversified low-fee index fund. Don't pay an advisor to pick stocks for you. Don't day-trade. Don't try to time the market. The evidence overwhelmingly supports passive investing for individual investors. (Your uncle who "beats the market" is probably either lucky or not counting his losses accurately.)

28.5 Connecting to personal finance

The financial system connects directly to your personal financial life:

Saving: when you save, you supply funds to the loanable funds market. Your bank account, your 401(k), your bond purchases — each is a form of supplying funds that someone else borrows.

Borrowing: when you take out a student loan, a mortgage, or a car loan, you demand funds from the market. The interest rate you pay reflects the risk you represent, the current supply and demand for funds, and the Fed's monetary policy.

Investing: when you buy stocks or bonds, you're participating in market-based financial intermediation. The return you earn reflects the risk you take and the efficiency of the market.

The personal finance takeaway: save early (compounding is powerful — Chapter 25's Rule of 70 applies to investments too), diversify (don't put all your money in one stock), keep fees low (high-fee funds consistently underperform), and don't panic during market downturns (selling in a panic locks in losses that would recover if you held on).

28.6 Where this is going

Chapter 29 completes Part VI with the deep treatment of inflation causes — the quantity theory of money, the Phillips curve, and the 2021–23 episode from a monetary perspective.

Key terms recap: loanable funds market — S&D model for borrowing and lending; real interest rate is the price saving — supply of funds; slopes upward with the interest rate investment — demand for funds; slopes downward with the interest rate crowding out — government borrowing displaces private investment real interest rate — nominal rate minus inflation bond — a loan from buyer to issuer; earns interest stock (equity) — ownership share in a firm; earns dividends and capital gains risk premium — extra return demanded for holding riskier assets diversification — spreading investments to reduce risk efficient market hypothesis — prices reflect all available information; you can't consistently beat the market

Themes touched: Markets power+imperfect (EMH breaks down during bubbles), Behavioral (loss aversion in investing), Affects daily life (your savings, your mortgage, your retirement).