Chapter 6 Markets, Prices, Supply, and Demand

1. Chapter 6 Markets, Prices, Supply, and Demand Macroeconomics - Barro Chapter 6

2. Macroeconomics - Barro Chapter 6

3. Markets in the Macroeconomy • Assuming that households perform all of the functions in the economy. • Each household runs a family business and uses labor, L, and capital, K, to produce goods, Y, through the production function. Y= A· F( K, L) Macroeconomics - Barro Chapter 6

4. Markets in the Macroeconomy • The Goods Market • Households sell all the goods they produce on a goods market. Then households buy back from this market the goods that they want. • Household buys goods for • consumption. • to increase the stock of goods in the form of capital used for production, called investment. Macroeconomics - Barro Chapter 6

5. Markets in the Macroeconomy • The Labor Market • Households supply labor on a labor market. • Assume that the quantity supplied, Ls, is a constant, L. Macroeconomics - Barro Chapter 6

6. Markets in the Macroeconomy • The Rental Market • Each household rents out all of the capital that it owns on a rental market. • We think of the capital offered on the rental market as the supply of capital services, Ks. Since we have assumed that each household rents out all of its capital, we have Ks= K. Macroeconomics - Barro Chapter 6

7. Markets in the Macroeconomy • The Bond Market • A borrowing household receives a loan from another household, whereas a lending household provides a loan to another household. • A household that makes a loan receives a piece of paper called a bond, and we call the market on which households borrow or lend the bond market. The holder of a bond, the lender, has a claim to the amount owed by the borrower. Macroeconomics - Barro Chapter 6

8. Money as a Medium of Exchange • We assume that the exchanges on each of these markets use a single form of medium of exchange. • A medium of exchange is an object held, not for its own sake, but rather to trade fairly soon for something else, such as goods and services. We call the medium of exchange in our model money. Macroeconomics - Barro Chapter 6

9. Money as a Medium of Exchange • Assume that money is just a piece of paper, analogous to a paper currency issued by a government. • Money is denominated in an arbitrary unit, such as a “dollar.” • Dollar amounts are in nominal terms. • Paper money earns no interest. Macroeconomics - Barro Chapter 6

10. Markets in the Macroeconomy • The sum of the individual holdings of money equals the aggregate quantity of money in the economy. • Assume, for now, that this aggregate quantity of money is a given constant. • The total money held by all households must end up equaling this constant. Macroeconomics - Barro Chapter 6

11. Markets and Prices • The Goods Market • The price in this market, denoted by P, expresses the number of dollars that exchange for one unit of goods. We call P the price level. Macroeconomics - Barro Chapter 6

12. Markets and Prices • The Goods Market • Y= A· F( K, L) • Since all of these goods are sold on the goods market, the variable Y will also represent the • Quantity of goods per year sold and bought on the goods market. • The quantity PYis the dollar value per year of the goods bought and sold on the goods market. Macroeconomics - Barro Chapter 6

13. Markets and Prices • The Goods Market • For a seller of goods, the price level, P, is the number of dollars obtained for each unit of goods sold. • For a buyer, P is the number of dollars paid per unit of goods. • Since P dollars buy 1 unit of goods, $1 buys 1/P units of goods. The Macroeconomics - Barro Chapter 6

14. Markets and Prices • The Goods Market • The expression 1/P is the value of $1 in terms of the goods that it buys. • M dollars exchange for ( M) · ( 1/ P) = M/ P • An expression like M/P is in real terms, in units of goods, whereas a quantity like M is in dollar or nominal terms. Macroeconomics - Barro Chapter 6

15. Markets and Prices • The Labor Market • Households buy and sell labor in the labor market at the dollar or nominal wage rate, w. • The real wage rate is w/P. Macroeconomics - Barro Chapter 6

16. Markets and Prices • The Rental Market • Households rent out capital, K, for dollars at the dollar or nominal rental price, R • A household that rents the amount of capital Kd pays the nominal amount RKdper year and then gets to use the capital as an input to production. • The real rental price is R/P. Macroeconomics - Barro Chapter 6

17. Markets and Prices • The Labor Market • Households buy and sell labor in the labor market at the dollar or nominal wage rate, w. • The real wage rate is w/P. Macroeconomics - Barro Chapter 6

18. Markets and Prices • The Bond Market • Each unit of bonds commits the borrower to repay $1 to the holder of the bond. This $1 is the principal of each bond. • The principal is the initial amount advanced on a loan. • All bonds have very short maturity, Macroeconomics - Barro Chapter 6

19. Markets and Prices • The Bond Market • Each unit of bonds commits the borrower to pay the holder a flow of interest payments of $i per year. • The variable i is the interest rate, which is the ratio of the interest payment, $i, to the principal $1. • The interest rate, i, can vary over time. Macroeconomics - Barro Chapter 6

20. Constructing the Budget Constraint • The quantities and prices determined on the four markets will determine household income. • Flows of income are sources of funds • Purchases of goods and assets are uses of funds • The total sources of funds must equal the total uses of funds. This equality is called the household budget constraint. Macroeconomics - Barro Chapter 6

21. Constructing the Budget Constraint • Income • Profits • Households may earn profit—an excess of revenue over costs—from their business activities. • Y= A· F( Kd, Ld) • π= PY − (wLd+ RKd) • π = P A· F( Kd, Ld) − ( wLd+ RKd) Macroeconomics - Barro Chapter 6

22. Constructing the Budget Constraint • Income • Wage income • If households supply the quantity of labor Ls to the labor market, they receive the nominal wage income of wLsper year. • Quantity of labor supplied is the fixed amount L, so nominal wage income is wL. Macroeconomics - Barro Chapter 6

23. Constructing the Budget Constraint • Income • Rental income • If households supply the quantity of capital Ksto the rental market they receive the nominal rental income of RKsper year. • Since households supply all of their available capital, K, to the rental market, so that Ks= K, the nominal rental income is RK. Macroeconomics - Barro Chapter 6

24. Constructing the Budget Constraint • Income • Rental income • The quantity δK of capital disappears each year. The dollar value of this lost capital is P· δK. • net nominal rental income= nominal rental income− value of depreciation • net nominal rental income = RK − δ P K • net nominal rental income = (R/ P)·P K − δ P K • net nominal rental income= ( R/ P − δ) · P K Macroeconomics - Barro Chapter 6

25. Constructing the Budget Constraint • Income • Rental income • rate of return on owning capital= R/ P − δ Macroeconomics - Barro Chapter 6

26. Constructing the Budget Constraint • Income • Interest Income • If a household’s nominal bond holdings are B, the flow of nominal interest income received is iB per year. • Since B equals zero for the whole economy, we have that the total of interest income equals zero. Macroeconomics - Barro Chapter 6

27. Constructing the Budget Constraint • Total income • Household nominal income= nominal profit + nominal wage income + nominal net rental income+ nominal interest income • Household nominal income = π+ wL + (R/P − δ) · PK + iB Macroeconomics - Barro Chapter 6

28. Constructing the Budget Constraint • Consumption • Households consume goods in the quantity C per year at price= P • Household nominal consumption= P C Macroeconomics - Barro Chapter 6

29. Constructing the Budget Constraint • Assets • Households hold assets in three forms: • money, M; • bonds, B; • ownership of capital, K. Macroeconomics - Barro Chapter 6

30. Constructing the Budget Constraint • Assets • We assume that households hold a fixed amount of money in dollar terms; that is, we assume that the change over time of a household’s nominal money holdings is zero • ∆M=0 Macroeconomics - Barro Chapter 6

31. Constructing the Budget Constraint • Assets • In considering whether to hold assets as bonds or capital, households would compare the rate of return on bonds, the interest rate, I, with the rate of return on ownership of capital, R/P − δ. • Rate of return on bonds= rate of return on ownership • i = R/ P − δ Macroeconomics - Barro Chapter 6

32. Constructing the Budget Constraint • Household nominal income= π + wL + i · ( B+ P K ) Macroeconomics - Barro Chapter 6

33. Constructing the Budget Constraint • Household Budget Constraint • nominal value of assets= M+ B+ P K • nominal saving to be the change over time in the nominal value of assets. • nominal saving= (∆nominal assets) = ∆M + ∆B + P·∆K Macroeconomics - Barro Chapter 6

34. Constructing the Budget Constraint • Household Budget Constraint • nominal saving= nominal income− nominal consumption • nominal saving= π+ wL + i · ( B+ P K ) − P C • ∆B + P ·∆K = π+ wL + i·( B+ PK ) − P C Macroeconomics - Barro Chapter 6

35. Constructing the Budget Constraint • Household Budget Constraint in Nominal Terms • PC + ∆B + P·∆K = π+ wL + i·( B+ P K ) • nominal consumption + nominal saving = nominal income Macroeconomics - Barro Chapter 6

36. Constructing the Budget Constraint • Household Budget Constraint real terms • C + ( 1/ P)·∆B+ ∆K = π/ P + ( w/P)·L + i·(B/P+K) • consumption + real saving = real income Macroeconomics - Barro Chapter 6

37. Constructing the Budget Constraint Macroeconomics - Barro Chapter 6

38. Clearing of the Markets for Labor and Capital Services • Profit Maximization • Real Profit • π/P = A·F(Kd,Ld) − (w/P) · Ld− (R/P) · Kd • real profit= output −real wage payments−real rental payments Macroeconomics - Barro Chapter 6

39. Clearing of the Markets for Labor and Capital Services Macroeconomics - Barro Chapter 6

40. Clearing of the Markets for Labor and Capital Services • The Labor Market • Demand for labor • ∆(π/P) = ∆[ A·F( Kd, Ld) ] − w/ P • = MPL − w/P • change in real profit= marginal product of labor− real wage rate Macroeconomics - Barro Chapter 6

41. Clearing of the Markets for Labor and Capital Services Macroeconomics - Barro Chapter 6

42. Clearing of the Markets for Labor and Capital Services • Supply of labor • We are assuming that each household supplies a fixed quantity of labor to the labor market. • Therefore, the aggregate or market supply of labor, Ls, is the given amount L. Macroeconomics - Barro Chapter 6

43. Clearing of the Markets for Labor and Capital Services • Clearing of the labor market • w/P is determined to equate the aggregate quantity of labor demanded, Ld, to the aggregate quantity supplied, L. • ( w/ P)* = MPL ( evaluated at L) Macroeconomics - Barro Chapter 6

44. Clearing of the Markets for Labor and Capital Services Macroeconomics - Barro Chapter 6

45. Clearing of the Markets for Labor and Capital Services • The Market for Capital Services • Demand for capital services • ∆(π/P) = ∆[ A·F(Kd, Ld) ] − R/P • = MPK − R/P • change in real profit= marginal product of capital− real rental price Macroeconomics - Barro Chapter 6

46. Clearing of the Markets for Labor and Capital Services Macroeconomics - Barro Chapter 6

47. Clearing of the Markets for Labor and Capital Services • The Market for Capital Services • Supply of capital services • For the economy as a whole, the aggregate quantity of capital, K, is given from past flows of investment. • In the short run, the aggregate or market quantity of capital services supplied, Ks, equals K. Macroeconomics - Barro Chapter 6

48. Clearing of the Markets for Labor and Capital Services • The Market for Capital Services • Clearing of the market for capital services • R/P will be determined to clear the market—that is, so that the aggregate quantity of capital services supplied, K, equals the aggregate quantity demanded, Kd • (R/P)* = MPK( evaluated at K) Macroeconomics - Barro Chapter 6

49. Clearing of the Markets for Labor and Capital Services Macroeconomics - Barro Chapter 6

50. Clearing of the Markets for Labor and Capital Services • The Market for Capital Services • The interest rate • i = R/P − δ • rate of return on bonds= rate of return on ownership of capital • i = MPK ( evaluated at K) − δ Macroeconomics - Barro Chapter 6