Goods and Financial Markets in the Short Run

Goods and Financial Markets – Understanding Demand and Short-Run Activity

• Fundamental Economic Questions regarding Short-Run Fluctuations:     * Why do changes in uncertainty or confidence lead to significant fluctuations in output?     * Why do government spending or monetary policies often result in effects that are larger than their initial impact?     * How are interest rates determined, and why do they, in specific circumstances, fail to stimulate the economy?

• Analytical Framework: This lecture utilizes simple frameworks to explore how demand, interest rates, and policy interventions shape economic activity in the short run.

• Short-Run Interactions: When analyzing year-to-year economic movements, economists focus on the cyclical relationship between production, income, and demand:     * Changes in the demand for goods drive changes in production.     * Changes in production lead to changes in the level of income.     * Changes in income, in turn, drive changes in the demand for goods.

The Composition and Identity of GDP

• Components of GDP:     * Consumption ($C$): Refers to goods and services purchased by consumers.     * Investment ($I$): Sometimes called fixed investment; it is the sum of residential investment and nonresidential investment.     * Government Spending ($G$): Includes purchases of goods and services by state and local governments. Notably, this excludes government transfers (like welfare or social security).     * Exports ($X$): Purchases of domestic (e.g., U.K.) goods and services by foreign entities.     * Imports ($IM$): Purchases of foreign goods and services by domestic consumers, firms, and the government.     * Net Exports ($X - IM$): Also known as the trade balance.         * Trade Surplus: Occurs when Exports > Imports.         * Trade Deficit: Occurs when Imports > Exports.     * Inventory Investment: Represents the difference between the goods produced and the goods sold within a period.

• U.K. GDP by Expenditure Component (Recent Estimates):     * Consumption ($C$): Approximately $61.7\%$ of GDP.     * Investment ($I$): Approximately $17.6\%$ of GDP.     * Government ($G$): Approximately $21.2\%$ of GDP.     * Exports ($X$): Approximately $32.6\%$ of GDP.     * Imports ($M$): Approximately $-33.7\%$ of GDP.     * Net Exports ($X - M$): Approximately $-1.1\%$ of GDP.

Mathematical Framework for the Demand for Goods

• The Demand Identity ($Z$):     * $Z \equiv C + I + G + X - IM$     * This identity defines total demand ($Z$) as the sum of consumption, investment, government spending, and net exports.

• Closed Economy Assumption: In a closed economy, exports and imports are zero ($X = IM = 0$), simplifying the identity to:     * $Z \equiv C + I + G$

• The Consumption Function ($C(Y_D)$,):     * Consumption is a behavioral function of disposable income ($Y_D$).     * Disposable income is defined as the income remaining after consumers receive government transfers and pay taxes.     * The linear relation is expressed as: $C = c_0 + c_1 Y_D$     * Propensity to Consume ($c_1$): The effect of an additional dollar of disposable income on consumption.     * Autonomous Consumption ($c_0$): The level of consumption if disposable income were zero. Changes in $c_0$ reflect shifts in consumption for a given income level (e.g., changes in consumer confidence).

• Relationship between Consumption and Disposable Income:     * Consumption increases with disposable income, but the increase is less than one-for-one (c_1 < 1).     * A lower value of $c_0$ shifts the entire consumption line downward.

• Disposable Income Equation:     * $Y_D \equiv Y - T$     * In this context, $Y$ represents income and $T$ represents taxes minus government transfers.

Variables and Equilibrium in the Goods Market

• Categorization of Variables:     * Endogenous Variables: Variables explained within the model that depend on other variables (e.g., $Y$ and $C$).     * Exogenous Variables: Variables taken as given and not explained by the model.         * Investment ($I$): Assumed exogenous in the short run, denoted as $I = \bar{I}$.         * Fiscal Policy ($G$ and $T$): Government spending and taxes are treated as exogenous because they are determined by policy decisions rather than economic behavior within the model.

• Equilibrium Condition:     * Equilibrium requires that production ($Y$) equals the demand for goods ($Z$).     * $Y = Z$     * Substituting the components into the equation for a closed economy:     * $Y = c_0 + c_1(Y - T) + \bar{I} + G$

• Solving for Equilibrium Output ($Y$):     * $Y = c_0 + c_1 Y - c_1 T + \bar{I} + G$     * $(1 - c_1)Y = c_0 + \bar{I} + G - c_1 T$     * $Y = \frac{1}{1 - c_1} \times [c_0 + \bar{I} + G - c_1 T]$

• Autonomous Spending: The term $[c_0 + \bar{I} + G - c_1 T]$ represents the part of demand that does not depend on output. Under a balanced budget ($G = T$), it is positive if 0 < c_1 < 1.

• The Multiplier: The term $\frac{1}{1 - c_1}$ is the multiplier.     * The multiplier increases as the marginal propensity to consume ($c_1$) approaches 1.     * Example: If $c_1 = 0.6$, the multiplier is $\frac{1}{1 - 0.6} = 2.5$. In this scenario, an increase in autonomous spending of $\pounds 1\,\text{billion}$ results in an output increase of $\pounds 2.5\,\text{billion}$.

Case Studies in Aggregate Demand Shocks

• The Lehman Bankruptcy and the Great Depression (2008):     * Following the bankruptcy of Lehman Brothers in September 2008, consumer fears led to an increase in saving regardless of current income levels.     * Google search data showed a massive spike in searches for "Great Depression."     * Consumption, particularly of durables, fell sharply in the United States from 2008:1 to 2009:3 even before disposable income changed significantly.

• Covid-19 and Demand:     * The pandemic led to a fall in autonomous consumption ($c_0$).     * The multiplier mechanism amplified this initial drop in spending, leading to a large recession even though prices and wages were slow to adjust.

Alternative Perspective: Investment Equals Saving ($IS$ Relation)

• Keynesian Model (1936): John Maynard Keynes proposed a model focusing on the relationship between investment and saving in The General Theory of Employment, Interest and Money.

• Private Saving ($S$): Defined as disposable income minus consumption.     * $S \equiv Y_D - C = Y - T - C$

• Public Saving: Defined as $T - G$.     * Budget Surplus: Public saving > 0.     * Budget Deficit: Public saving < 0.

• Deriving the IS Relation:     * Start with $Y = C + I + G$.     * Subtract $T$ and $C$ from both sides:     * $Y - T - C = I + G - T$     * Since the left side is private saving ($S$), the equilibrium condition is:     * $S = I + G - T$ or $I = S + (T - G)$     * This states that Investment equals the sum of Private and Public Saving.

Financial Markets and the Demand for Money

• Asset Choice: Individuals choose between two assets: Money and Bonds.     * Money: Used for transactions; pays no interest. Includes currency and bank deposits.     * Bonds: Pay an interest rate ($i$) but cannot be used for direct transactions.     * The Trade-off: Choosing between liquidity (money) and returns (bonds).

• Determinants of Money Demand ($M^d$):     * Level of transactions (measured by nominal income, $\pounds Y$).     * The interest rate on bonds ($i$).     * Equation: $M^d = \pounds Y L(i)$, where $L(i)$ is a decreasing function of the interest rate.

• Behaviors in Money Demand:     * An increase in the interest rate decreases $M^d$ (people prefer interest-bearing bonds).     * An increase in nominal income shifts the $M^d$ curve to the right.     * UK Example (2022-2023): As interest rates rose sharply, the opportunity cost of holding money in current accounts increased, causing households to shift wealth to savings accounts and money market funds.

Determination of the Interest Rate by the Central Bank

• Money Market Equilibrium:     * The Central Bank (e.g., Bank of England or the Fed) supplies a fixed amount of money ($M^s$).     * Equilibrium occurs where $M^s = M^d$, or $M = \pounds Y L(i)$.     * The interest rate adjusts to equate the supply and demand for money.

• Shifts in Equilibrium:     * Increase in Nominal Income: Shifts $M^d$ rightward, leading to a higher interest rate for a fixed money supply.     * Increase in Money Supply: Shifts the supply curve rightward, leading to a lower interest rate.

• Open Market Operations:     * Expansionary: The central bank buys bonds, paying for them by creating money. This increases the money supply and both assets and liabilities on the bank's balance sheet.     * Contractionary: The central bank sells bonds to decrease the money supply.

• Bond Prices and Interest Rates:     * Formula: For a bond paying $\pounds 100$ in one year, $i = \frac{\pounds 100 - \pounds P_B}{\pounds P_B}$, where $\pounds P_B$ is the current price.     * There is an inverse relationship: Higher bond prices imply lower interest rates; higher interest rates imply lower current bond prices.

• Modern Central Banking Practice: Most modern central banks (BoE, Fed) choose a target interest rate and adjust the money supply as needed to achieve that rate.

Commercial Banks and the Money Market

• Banks as Intermediaries: Banks receive deposits (liabilities) and hold assets including loans, reserves, and bonds.

• Transmission of Policy: Banks transmit monetary policy to the wider economy. When the demand for deposits changes, the money market conditions change, and the interest rate adjusts to ensure balance.

• Cryptocurrency Debate: Cryptocurrencies are currently unlikely to replace national money because:     1. Prices, wages, and contracts are still denominated in national currencies; crypto volatility is too high.     2. They are often costly and inefficient for large-scale payments with limited transaction capacity.     3. Central banks and governments have strong incentives to maintain control over monetary policy and official currency.     * Current Status: Crypto behaves more like speculative financial assets than money.

The Liquidity Trap

• Zero Lower Bound: Conventional monetary policy hits a limit when interest rates fall to zero.

• Mechanism: At a zero interest rate, individuals are indifferent between holding bonds and money. The money demand curve becomes horizontal.

• Ineffectiveness: Further increases in the money supply have no effect on the interest rate.

• UK Context: The UK economy reached the zero lower bound following the 2008 Global Financial Crisis and during the Covid-19 pandemic.

Summary Takeaways

• Short-run output is determined by aggregate demand.

• In the goods market, equilibrium is reached when production equals demand ($Y = Z$), influenced by autonomous spending and the multiplier.

• In financial markets, the interest rate is determined by the interaction of money supply and money demand.

• The interest rate acts as the link between financial conditions and real economic activity.

• The Liquidity Trap represents a boundary where interest rates can no longer adjust downward to stimulate the economy.