1 Entrada y salida Puntos sobresalientes 1. A medida que entran nuevas empresas a la industria, el precio cae y los beneficios económicos de cada empresa existente disminuyen. 2. A medida que las empresas abandonan una industria, el precio se eleva y la pérdida económica de cada empresa que permanece dentro de la industria tiende a disminuir.

2 Equilibrio de largo plazo u El equilibrio de largo plazo en una industria competitiva ocurre cuando las empresas obtienen un beneficio normal o el beneficio económico es nulo. u Por tanto, en el equilibrio de largo plazo en una industria competitiva, las empresas ni entran ni abandonan la industria, y tampoco amplían ni reducen su tamaño.

3 Competencia y eficiencia El uso eficiente de los recursos requiere de tres condiciones: 1. Los consumidores sean eficientes 2. Las empresas sean eficientes 3. El mercado esté en equilibrio

4 Excedente del Consumidor El excedente del cosumidor u es una medida de las ganancias del consumidor. u Es la diferencia entre lo que esta dispuesto a pagar y lo que en realidad paga. u Ejemplo: si el consumidor valora un bien en $8, y paga solamente $4, el Excedente del consumidor es igual a 4.

5 Geometría del excedente del consumidor

6 Excedente del productor El excedente del productor u es una medida de las ganancias del productor. u Es la diferencia entre el precio que esta dispuesto a vender y el precio que en realidad vende. u Ejemplo: si el productor valora vender el bien en $8, y lo vende paga en $10, el Excedente del productor es $2.

7 Geometría del excedente del productor

8 Cantidad Precio P*P* Eficiencia de la competencia O = CM D Q*Q* Excedente del consumidor Excedente del productor B0B0 Asignación eficiente C0C0 Q0Q0

9 Market Equilibrium u A market is in equilibrium when total quantity demanded by buyers equals total quantity supplied by sellers.

10 Market Equilibrium p D(p) q=D(p) Market demand

11 Market Equilibrium p S(p) Market supply q=S(p)

12 Market Equilibrium p D(p), S(p) q=D(p) Market demand Market supply q=S(p)

13 Market Equilibrium p D(p), S(p) q=D(p) Market demand Market supply q=S(p) p* q*

14 Market Equilibrium p D(p), S(p) q=D(p) Market demand Market supply q=S(p) p* q* D(p*) = S(p*); the market is in equilibrium.

15 Market Equilibrium p D(p), S(p) q=D(p) Market demand Market supply q=S(p) p* S(p’) D(p’) < S(p’); an excess of quantity supplied over quantity demanded. p’ D(p’)

16 Market Equilibrium p D(p), S(p) q=D(p) Market demand Market supply q=S(p) p* S(p’) D(p’) < S(p’); an excess of quantity supplied over quantity demanded. p’ D(p’) Market price must fall towards p*.

17 Market Equilibrium p D(p), S(p) q=D(p) Market demand Market supply q=S(p) p* D(p”) D(p”) > S(p”); an excess of quantity demanded over quantity supplied. p” S(p”)

18 Market Equilibrium p D(p), S(p) q=D(p) Market demand Market supply q=S(p) p* D(p”) D(p”) > S(p”); an excess of quantity demanded over quantity supplied. p” S(p”) Market price must rise towards p*.

19 Market Equilibrium u An example of calculating a market equilibrium when the market demand and supply curves are linear.

20 Market Equilibrium p D(p), S(p) D(p) = a-bp Market demand Market supply S(p) = c+dp p* q*

21 Market Equilibrium p D(p), S(p) D(p) = a-bp Market demand Market supply S(p) = c+dp p* q* What are the values of p* and q*?

22 Market Equilibrium At the equilibrium price p*, D(p*) = S(p*).

23 Market Equilibrium At the equilibrium price p*, D(p*) = S(p*). That is,

24 Market Equilibrium At the equilibrium price p*, D(p*) = S(p*). That is, which gives

25 Market Equilibrium At the equilibrium price p*, D(p*) = S(p*). That is, which gives and

26 Market Equilibrium p D(p), S(p) D(p) = a-bp Market demand Market supply S(p) = c+dp

27 Market Equilibrium One special case: 1. quantity supplied is fixed, independent of the market price, and

28 Market Equilibrium Market quantity supplied is fixed, independent of price. p qq*

29 Market Equilibrium S(p) = c+dp, so d=0 and S(p)  c. p qq* = c Market quantity supplied is fixed, independent of price.

30 Market Equilibrium S(p) = c+dp, so d=0 and S(p)  c. p qq* = c Market demand Market quantity supplied is fixed, independent of price. D(p) = a-bp

31 Market Equilibrium S(p) = c+dp, so d=0 and S(p)  c. p q p* D(p) = a-bp Market demand q* = c Market quantity supplied is fixed, independent of price.

32 Market Equilibrium S(p) = c+dp, so d=0 and S(p)  c. p q p* = (a-c)/b Market demand q* = c Market quantity supplied is fixed, independent of price. D(p) = a-bp

33 Market Equilibrium S(p) = c+dp, so d=0 and S(p)  c. p q D(p) = a-bp Market demand q* = c p* = (a-c)/b Market quantity supplied is fixed, independent of price.

34 Market Equilibrium S(p) = c+dp, so d=0 and S(p)  c. p q Market demand q* = c with d = 0 give p* = (a-c)/b Market quantity supplied is fixed, independent of price. D(p) = a-bp

35 Quantity Taxes u What is the effect of a quantity tax on a market’s equilibrium? u How are prices affected? u How is the quantity traded affected? u Who pays the tax? u How are gains-to-trade altered?

36 Quantity Taxes u Two kinds of taxes that one might impose: quantity taxes and value taxes (ad valorem taxes) u A quantity tax is a tax levied per unit of quantity bought or sold. The gasoline tax is 12 cents a gallon. u If the consumer is paying p b =$1.50 per gallon of gasoline, the supplier is getting p s =$ =$1.38 per gallon.

37 Quantity Taxes u In general, if t is the amount of the quantity tax per unit sold, then

38 Quantity Taxes u A value tax is a tax expressed in percentage units.

39 Quantity Taxes u Even with a tax the market must clear. u I.e. quantity demanded by buyers at price p b must equal quantity supplied by sellers at price p s.

40 Quantity Taxes and describe the market’s equilibrium. Notice these conditions apply no matter if the tax is levied on sellers or on buyers.

41 Quantity Taxes & Market Equilibrium p D(p), S(p) Market demand Market supply p* q* No tax

42 Quantity Taxes & Market Equilibrium p D(p), S(p) Market demand Market supply p* q* $t An supplier tax raises the market supply curve by $t

43 Quantity Taxes & Market Equilibrium p D(p), S(p) Market demand Market supply p* q* An supplier tax raises the market supply curve by $t, raises the buyers’ price and lowers the quantity traded. $t pbpb qtqt

44 Quantity Taxes & Market Equilibrium p D(p), S(p) Market demand Market supply p* q* An supplier tax raises the market supply curve by $t, raises the buyers’ price and lowers the quantity traded. $t pbpb qtqt And sellers receive only p s = p b - t. psps

45 Quantity Taxes & Market Equilibrium p D(p), S(p) Market demand Market supply p* q* No tax

46 Quantity Taxes & Market Equilibrium p D(p), S(p) Market demand Market supply p* q* An sales tax lowers the market demand curve by $t $t

47 Quantity Taxes & Market Equilibrium p D(p), S(p) Market demand Market supply p* q* An sales tax lowers the market demand curve by $t, lowers the sellers’ price and reduces the quantity traded. $t qtqt psps

48 Quantity Taxes & Market Equilibrium p D(p), S(p) Market demand Market supply p* q* An sales tax lowers the market demand curve by $t, lowers the sellers’ price and reduces the quantity traded. $t pbpb pbpb qtqt pbpb And buyers pay p b = p s + t. psps

49 Quantity Taxes & Market Equilibrium p D(p), S(p) Market demand Market supply p* q* A sales tax levied at rate $t has the same effects on the market’s equilibrium as does an supplier tax levied at rate $t. $t pbpb pbpb qtqt pbpb psps

50 Pérdida irrecuperable = $90 millones O + impuesto Por qué no se grava el jugo de naranja Cantidad (millones de litros al día) Precio (centavos por litro) O D Impuesto = $0.90 por litro

51 Eficiencia de la competencia perfecta u La competencia perfecta permite el uso eficiente de los recursos si no hay beneficios externos ni costos externos Hay tres principales obstáculos a la eficiencia: 1. Monopolio 2. Bienes públicos 3. Externalidades positivas o negativas