The Japanese Economic Review Vol. 51, No. 4, December 2000 THE OPTIMAL TARIFF FORMULA IN A TWO-PERIOD ECONOMY By TADASHI INOUE University of Tsukuba, Ibaraki, Japan The optimal tariff formula is derived for a large country trading both consumption goods and an investment good in a two-period economy. The formula greatly simpli®es the results of the standard one-period economy where both consumption goods and real capital are traded with or without a non-traded good; in particular, the results do not depend on the relative intensities of the two goods. JEL Classi®cation Numbers: D11, F11, F34. 1. Introduction This paper tries to investigate the formula of the optimal tariff/subsidy in a two-period economy. This is a generalization of the optimal tariff and tax formula for a large country trading both consumption commodities and real capital, obtained by Jones (1967), Kemp (1969), Chipman (1972) and Inoue and Kiyono (1988), among others. Re¯ecting the assumption that it is not capital itself but the investment good that is traded in our two-period economy, optimal tariff con®gurations in the two-period economy are different to some extent from those of the standard one-period economy. To be more precise, some of the signs of the optimal tariff formula for investment goods are different, though the signs of the optimal tariff formula for consumption goods are the same. Also, these results simplify the classi®cations greatly. In particular, they do not depend on the ranking of factor intensities of the two goods. Section 2 sets out the assumptions of the model. 2. The model Let there exist two countries (the home country and the foreign country), two periods (period 1 present period, and period 2 future period), one consumption good in each period and one investment good only in period 1. Goods are produced employing labour and capital in both periods with neoclassical technology (constant returns to scale and concave production functions); l, the labour endowments of the home country, are constant over time while a, the capital endowments, increase in period 2 by v, the amount of investment good employed in period 2. Capital depreciation is assumed away for simpli®cation. Let y1 be the amount of the consumption good produced in period 1 (good 1) in the home country and p1 be its domestic price, and let z be the amount of the investment good produced in period 1 in the home country and q be its domestic price. Each country is assumed to lend and borrow money at the common international interest rate r, which is the discount rate for future factor and commodity prices. But this is not a monetary model. Money is used only to exchange present goods for future goods. ± 596 ± # Japanese Economic Association 2000. Published by Blackwell Publishers, 108 Cowley Road, Oxford OX4 1JF, UK. T. Inoue: The Optimal Tariff Formula in a Two-period Economy Let y2 be the amount of the consumption good produced in period 2 (good 2) in the home country and p2 be its present domestic price; i.e., p (1 r)ÿ1 p^2 where p^2 is the current domestic price of good 2. Both consumption good and investment good are assumed to be tradable. Let v be the amount of the investment good used to produce the consumption good in period 2 in the home country and k v ÿ z (resp., z ÿ v) be the amount of imports (resp., exports) of the investment good in period 1 if k . 0 (resp., if ÿk z ÿ v . 0). Let ð be the present-value revenue function of the home country so that: ð ð( p1 , p2 , q, ù) maxf p1 y1 p2 y2 ÿ q(v ÿ z)j y1 f 1 (l11 , a1 ), z f 2 (l21 , a2 ), y2 f (l, a v), l11 l21 l, a1 a2 ag where ù (l, a) is the endowment vector in period 1. Here f 1 and f 2 are, respectively, the production functions of the consumption good and investment good in period 1, and f is the production function of the consumption good in period 2. All production functions are assumed to be twice continuously differentiable. Furthermore, l11 and a1 are, respectively, the amount of labour and capital employed to produce y1 units of the consumption good in period 1; similarly, l21 and a2 are, respectively, the amount of labour and capital employed to produce z units of the investment good in period 1. Let w i and ri be the present domestic prices of labour and capital in period i in the home country, i 1, 2. (Hence w2 (1 r)ÿ1 w^2 , and r2 (1 r)ÿ1 r^2 hold where ^2 and r^2 are, respectively, the current prices of labour and capital in period 2.) w Here it is in order to explain the present-value revenue function ð. Just as in a oneperiod static model, from national accounting identities we observe GNE GNP GNI, i.e., p : c ð wl ra where p : c is the inner product of p ( p1 , p2 ), c (c1 , c2 ), w w1 w2 and r r1 r2 . In a two-period model the present-value revenue function is the sum of the revenue of consumption goods and the net export of the investment good. Especially in autarky, ð is the sum of the revenue of consumption goods only.1 Here p : cÿð0 implies that trade balance is attained not in each period but over the entire time horizon. Perfect competition is assumed to prevail in both the commodity and factor markets in each country as well as in the world economy in each period. The world markets of consumption goods in each period and of the investment good in period 1, and the markets of labour and capital of each country in each period, are all assumed to clear. Only the external balance is not assumed to clear in each period, but rather to clear over time. Since the investment good produced in period 1 is the same as the increase in the capital endowment in period 2 in terms of production ef®ciency, perfect competition in the investment good and capital markets leads to: q r2 (1) in equilibrium. 1 For the equality between p : c and ð in the two-period closed model, see e.g. Woodland (1982, pp. 469±470). ± 597 ± # Japanese Economic Association 2000. The Japanese Economic Review Throughout the paper, the foreign country is assumed to retain free commodity trade, so that P : C P : Y Qk (2) holds where P (P1 , P2 ), C (C1 , C2 ) and Y (Y1 , Y2 ). Pi is the international (foreign) present value of the price of consumption good in period i, i 1, 2. C i and Y i are, respectively, the amount of the consumption and the amount of production of the consumption good in the foreign country in period i, i 1, 2, and Q is the international (foreign) price of the investment good. Here, P : C is the inner product of P and C. Henceforth in general capital letters are used to express the variables and parameters of the foreign country. Let e( p, u) minf p : cju(c) > ug (3) be the expenditure function of the home country, where p ( p1 , p2 ) is the price vector of the consumption good, and c (c1 , c2 ) is the consumption vector of the home country; u is the social utility function of the home country. The social utility function is concave and strictly increasing in c in each country. Each consumption good is assumed to be normal in each country. Let xi c i ÿ yi , i 1, 2, be the excess demand for the consumption good in period i. xi . 0 (resp., , 0) means that the home country imports (resp., exports) the consumption good in period i. Throughout the paper, the consumption good in period 2 is the numeraire so that p2 P2 1 always holds. From this equation, the interest rate r is seen to equal (1 ÿ P1 )=P1 for both countries. If the consumption good is imported (resp., exported), p1 (1 ô )P1 (resp., (1 ô) p1 P1 ) holds where ô (resp., ô) is the tariff on imports (resp., the export tax). I adopt the convention that (1 ô)(1 ô ) 1 always holds so that ô , 0 means either that the export of good 1 is subsidized at a rate of ÿ100ô%, or that there exists a duty of 100ô % on imports of good 1 where ô ÿô=(1 ô). Similarly q (1 t )Q (resp., (1 t)q Q) holds if the investment good is the home imported (resp., exported) good, with t (resp., t) being the import tariff (resp., export tax) on the investment good. I adopt the convention that (1 t)(1 t ) 1 always holds. (t , 0 means either a ÿ100t% rate of subsidy for the export of the investment good, or a 100t % rate of tariff for its import where t ÿt=(1 t).) By de®nition, we then observe m p : c P : c ô P c ð( p , p , q, ù) ô P x t Qk, (4) 1 1 1 2 1 1 where m is the national wealth which is composed of the revenue ð, the tariff revenue of the consumption good ô P1 x1 and the tariff revenue of the investment good t Qk. Here it is to be noted that the equilibrium conditions for good 1 and investment good determine their prices P1 and Q.2 2 Let h i and H i be, respectively, the home and foreign demand functions for good i so that c i h i ( p1 , p2 , q, m) and C i H i (P1 , P2 , Q, M), where M P : C Ð(P1 , P2 , Q, Ù). Then h i ( p1 , p2 , q, m) H i (P1 , P2 , Q, M) ð1 ( p1 , p2 , q, ù) Ð1 (P1 , P2 , Q, Ù), k K ð3 ( p1 , p2 , q, ù) Ð3 (P1 , P2 , Q, Ù) 0, equation (4) and M Ð(P1 , P2 , Q, Ù) de®ne implicitly P1 and Q. ± 598 ± # Japanese Economic Association 2000. T. Inoue: The Optimal Tariff Formula in a Two-period Economy 3. Optimal tariff con®gurations I deal with a large home country which can manipulate terms of trade by tariff/subsidy policy. In particular, I investigate the optimal tariff con®gurations for the home country, which is large enough to change the international price P1 and the level of imports of the investment good by manipulating the level of tariff rates ô and t on the consumption good and investment good in period 1. (Henceforth I follow essentially the arguments of Chipman, 1972, and Inoue and Kiyono, 1988.) By totally differentiating the social utility function of the home country u u(c1 , c2 ), assuming that utility is maximized subject to the budget constraint m p : c, I obtain du p1 dc1 p2 dc2 , where the marginal utility of national wealth m is assumed to be unity without loss of generality. By substituting c i xi yi ÿX i yi , i 1, 2, into the above equation, it follows that du p1 d y1 p2 d y2 ÿ p1 dX 1 ÿ p2 dX 2 : Furthermore, since p1 d y1 p2 d y2 ÿ qdk 0 holds for a given ù, the above is reduced to du qdk ( p1 ÿ P1 )dx1 ÿ P1 dC1 ÿ P2 dC2 P1 dY1 P2 dY2 : (5) Here, by totally differentiating (2), while observing that P1 dY1 P2 dY2 Qdk 0 holds for a given foreign factor endowment vector Ù (L, A), I obtain P1 dC1 P2 dC2 ÿX 1 dP1 ÿ X 2 dP2 kdQ: (6) Substituting this into (5) and noting that dP2 0, I observe du [(q ÿ Q)dk ÿ ( p1 ÿ P1 )dX 1 ] (X 1 dP1 ÿ kdQ): (7) Equation (7) is Jones's (1967) equation (6) and Inoue and Kiyono's (1988) equation (15). Next, I note that (8) X C (P , P , u ) ÿ Y (P , Q) 1 1 1 2 1 1 holds, where C1 C1 (P1 , P2 , u ) is the compensated demand function for the consumption good in period 1 in the foreign country, u U (C1 , C2 ) being the foreign social utility function, with du P1 dC1 P2 dC2 , Y1 Y1 (P1 , Q) being the foreign supply function of that good, and k Z(P1 , Q) ÿ V (P2 , Q) (9) where Z Z(P1 , Q) is the foreign supply function of the investment good and V is its demand function (which is de®ned indirectly by the foreign counterpart of (1) and P2 @ f (L, A V )=@(A V ) Q). I therefore observe that (9) implicitly de®nes Q to be a function of P1 and k, and hence by (8) so does X 1 with X 11 ± 599 ± # Japanese Economic Association 2000. The Japanese Economic Review @ X 1 =@ P1 S11 ÿ (Y11 Y12 Q1 ) ÿ H 1 M (X 1 ÿ kQ1 ), where S11 , 0 is the Slutsky substitution term (i.e., S11 @C1 (P1 , P2 , u )=@ P1 ), Y11 @Y1 =@ P1 . 0, Y12 @Y1 =@Q , 0, Q1 @Q=@ P1 Z 1 =(V2 ÿ Z 2 ) . 0 and H 1 M @ H 1 (P1 , P2 , M)=@ M . 0, Q k @Q=@ k ÿ1=(V2 ÿ Z 2 ) ÿQ1 = Z 1 . 0, X 1 k @ X 1 =@ k ( H 1 M k ÿ Z 1 )Q k , Z 1 @ Z=@ P1 , 0, V2 @V =@Q , 0 and Z 2 @ Z=@Q . 0. (For the derivation of these equations, see Appendix A.) Hence (7) is rewritten as du (@u=@ P1 )dP1 (@u=@ k)dk, (10) with @u=@ P1 X 1 ÿ ( p1 ÿ P1 )X 11 ÿ kQ1 , and @u=@ k ÿ[(Q ÿ q) ( p1 ÿ P1 )X 1 K kQ K ], and hence (11) @u=@ P X [1 ÿ ( p ÿ P )ç =P ì ã ], 1 1 1 1 1 1 1 where ç1 X 11 P1 =X 1 , ì ÿQk=PX 1 and ã1 Q1 P1 =Q and " # ( p1 ÿ P1 )ã1 p 1 ä m m2 , @u=@ k q ÿ Q 1 P1 P1 1 (12) where ä kQ K =Q and mi Pi H iM (the foreign marginal propensity to consume the consumption good in period i.) Equation (10) is a generalization of Jones's (1967) equation (9), Chipman's (1972) equations (5.5), (5.6) and (5.7), and Inoue and Kiyono's (1988) equation (18). Equation (11) is the same as Inoue and Kiyono's (1988) equation (19-1), while (12) is different from their equation (20-1). Denote å1 ì ã1 ÿ(k=X 1 )Q1 , åk ÿ Z 1 P1 =k. Then ã1 åk ä holds so that å1 ì åk ä follows. By letting @u=@ P1 0 and @u=@ k 0, I obtain the optimal taxes ô for the consumption good and t for the investment good when the home country exports both goods in period 1: (13) ô ÿ(1 å )=(ç 1 å ) 1 1 1 and ÿ[ç (m1 åk )(1 å1 )]ä : t 1 ç1 [ç1 (m1 åk )(1 å1 )]ä (14) When the home country imports the consumption good in period 1, the optimal import tariff ô is: (15) ô ÿô=(ô 1) (1 å1 )=ç1 , and similarly, the optimal import tariff for the investment good t is: (16) t ÿt=(1 t) [ç1 (m1 åk )(1 å1 )]ä =ç1 : The optimal tariff formulae ô and ô for the consumption good are the same as the standard case, while those for the investment good, t and t , are different.3 By letting @u=@ P1 0, I obtain 3 In the standard case (i.e. the one-period economy), when the home country imports (resp., exports) capital, with ^t (resp., ^t) being the tax on rental price of capital, Q (1 ÿ ^t )q (resp., q (1 ÿ ^t )Q) holds so that t (resp., t) in my notation equals ^t =(1 ÿ ^t ) (resp., ^t=(1 ÿ ^t )). However, t and t in (14) and (16) are different from ^t=(1 ÿ ^t ) and ^t =(1 ÿ ^t ). The latter in the standard case equal, respectively, ÿã1 (1 å1 )=[ç1 ã1 (1 å1 )] and [ã1 (1 å1 )]=ç in my notation. (For this, see e.g. Inoue and Kiyono's (1988) equations (22-1), (23-1) and (24-1).) ± 600 ± # Japanese Economic Association 2000. T. Inoue: The Optimal Tariff Formula in a Two-period Economy p1 X 11 =X 1 1 ç1 å1 : (17) Furthermore, from the de®nition of X11 and (17), I see that p1 m1 m2 , 0 X 11 [S11 ÿ (Y11 Y12 )Q1 ]= P1 (18) follows.4 Hence I obtain X 1 . 0 , ç1 , 0: Furthermore, by de®nition, I observe that ã å ä . 0, 1 k åk . 0 , k . 0, (19) ì . 0 , kX 1 , 0 , å1 . 0, (20) ç1 , 0 , X 1 : X 11 , 0 , 1 ç1 å1 , 0 , X 1 . 0: (21) and Now I obtain the following con®gurations of the optimal tariff and tax formula for both the consumption good and the investment good in period 1. Theorem 1 Case 1: X 1 . 0 (The home country exports (a) å1 . 0 (b) ÿ1 , å1 , 0 (i) 0 , ÿç1 =(1 å1 ) ÿ m1 , åk (ii) åk , ÿç1 =(1 å1 ) ÿ m1 (c) å , ÿ1 the consumption good in period 1) Case 2: X 1 , 0 (The home country imports (a) å1 . 0 (b) ÿ1 , å1 , 0 (i) ÿç1 =(1 å1 ) ÿ m1 , åk (ii) åk , ÿç1 =(1 å1 ) ÿ m1 , 0 (c) å , ÿ1 the consumption good in period 1) k . 0, ô . 0, t . 0 k , 0, ô . 0 1 1 k , 0, ô . 0, t . 0 k . 0, ô . 0 t . 0 t , 0 k . 0, ô , 0, t . 0 t,0 t.0 k , 0, ô , 0, t . 0 (For the derivation of Cases 1 and 2, see Appendix B.) 4 Equation (18) follows from X 11 S11 ÿ (Y11 Y12 Q1 ) ÿ H 1 M X 1 (1 å1 ), equation (15) and Y11 Y12 Q1 . 0. The last inequality is obtained from Q Q1 P1 Q2 P2 , as explained below. Here, the homogeneity of degree 1 of Q in (P1 , P2 ) follows from the homogeneity of degree 1 of the revenue function Ð(P1 , P2 , Q, Ù) and the homogeneity of degree 0 of its derivative Ð Q Z(P1 , Q) ÿ V (P2 , Q) k in (P1 , P2 , Q). The latter equation implies that Q1 Z 1 =(V2 ÿ Z 2 ) . 0 and Q2 @Q=@ P2 ÿV1 =(V2 ÿ Z 2 ) . 0 and hence both Q1 and Q2 are positive. Noting Y12 , 0, it follows that Y11 Y12 Q1 . Y11 Y12 Q=P1 (Y11 P1 Y12 Q)=P1 0. (Let Ð(P1 , Q, Ù) maxfP1 Y1 QZjY1 F1 (L11 , A), Z F2 (L21 , A2 ), L11 L21 < L, A1 A2 < Ag. Then Ð1 Y1 is homogeneous of degree 0 in (P1 , Q), which implies Y11 P1 Y12 Q 0, Y11 . 0 and Y12 , 0:) ± 601 ± # Japanese Economic Association 2000. The Japanese Economic Review These results coincide with the standard case (see e.g. Chipman, 1972, and Inoue and Kiyono, 1988), except for (i) and (ii) of (b) where ÿ1 , å1 , 0 for both X 1 . 0 and X 1 , 0. In that case, for X 1 . 0, t . 0 for (b)(i) and t , 0 for (b)(ii), and for X 1 , 0, t , 0 for (b)(i) and t . 0 for (b)(ii), while in the standard case signs of t and t are opposite. (The signs of ô and ô are always the same.) However, as is seen from (20), since the signs of k and å1 are the opposite (resp., the same) for X 1 . 0 (resp., X 1 , 0), the above results greatly simplify the classi®cation of the optimal tariff combinations in comparison with the standard case, where, for three cases of the values of å1 , the sign of k can be positive as well as negative depending on the ranking of the factor intensities. 4. Concluding remarks Of course, the results obtained so far have some limitations; for example, the number of commodities, factors and periods should be more generalized. I do not have to assume that the foreign country retains free trade: it can also adopt tariff policies to maximize its utility. These generalizations should be followed up as a next step. Appendix A It is easy to obtain from equation (9) that Q1 Z 1 =(V2 ÿ Z 2 ) . 0 with Z 1 @ Z=@ P1 , 0, Z 2 @ Z=@Q . 0, V2 @V =@Q , 0 and Q k ÿ1=(V2 ÿ Z 2 ) ÿQ1 = Z 1 . 0. Noting from (6) that du P1 dC1 P2 dC2 ÿX 1 dP1 kdQ, (A1) then, by partially differentiating (8), it follows that X 11 S11 C1u uP1 ÿ Y11 ÿ Y12 Q1 , where C1u @C1 =@u and uP1 @u =@ P1 . Here, from the two identities E(P1 , P2 , u ) P1 C1 (P1 , P2 , u ) P2 C2 (P1 , P2 , u ) and H i (P1 , P2 , E(P1 , P2 , u )) C i (P1 , P2 , u), i 1, 2, while utilizing (A1), I observe that E u @ E=@u 1 and H iM @ H i =@ M C iu, i 1, 2, uP1 ÿX 1 kQ1 from (A1), and hence X 11 S11 ÿ (Y11 Y12 Q1 ) ÿ H 1 M (X 1 ÿ kQ1 ). Similarly, by partially differentiating (8) with respect to k, we obtain: X 1 k @ X 1 =@ k C1u uk ÿ Y12 Q k ( H 1 M k ÿ Z 1 )Q k (A2) where uk @u =@ k kQ k from (A1), and Y12 @Y1 =@Q @ 2 Ð(P1 , P2 , Q)= @ P1 @Q @ 2 Ð(P1 , P2 , Q)=@Q@ P1 @( Z ÿ V )=@ P1 @ Z=@ P1 Z 1 , 0 from the property of the revenue function Ð. ± 602 ± # Japanese Economic Association 2000. T. Inoue: The Optimal Tariff Formula in a Two-period Economy Appendix B For Case 1 (X 1 . 0), ç1 , 0 always holds from (18). Furthermore, from (20) I obtain å1 . 0 , k , 0. Hence it follows that (a) å1 . 0, k ,0 k .0 (b) ÿ1 , å1 , 0, k . 0: (c) å , ÿ1, 1 And similarly, for Case (a) å1 . 0, (b) ÿ1 , å1 , 0, (c) å , ÿ1, 1 2 (X 1 , 0), k .0 k ,0 k , 0: The signs of ô and ô follow from (13), (15) and (21). As for the signs of t and t , I observe from (12) with @u=@ k 0 and (A2) that p1 m m2 k ÿ ( p1 ÿ P1 ) Z 1 Q k : Qÿqÿ P1 1 Noting that 0 , m , 1, i 1, 2, Z , 0 and Q . 0, I observe that 1 i k k.0 and p1 . P1 ) Q , q (i:e:, t . 0) k ,0 and p1 , P1 ) Q . q (i:e:, t . 0): and In other words, it follows that k.0 and ô , 0 (resp:, ô . 0) in X 1 . 0 (resp:, X 1 , 0) ) t . 0, (A3) ô . 0 (resp:, ô , 0) in X 1 . 0 (resp:, X 1 , 0) ) t . 0: (A4) and k ,0 and The signs of t and t for (a) and (c) for Cases 1 and 2 are obtained from (A3) and (A4). For (b), ÿ1 , å1 , 0 of Cases 1 and 2, I observe that t . 0 , t , 0 , å . ÿç =(1 å ) ÿ m k 1 1 1 from (15), noting 1 t . 0 by assumption. Here it is to be noted that ÿç1 =(1 å1 ) ÿ m1 . 0 (resp., , 0) for Case 1 (resp. 2) hold always. Final version accepted 10 December 1998. REFERENCES Chipman, J. S. (1972) ``The Theory of Exploitative Trade and Investment Policies: A Reformation and Synthesis'', in L. E. Dimarco, ed., International Economics and Development: Essays in Honor of Raul Prebisch, New York and London: Academic Press, pp. 209±244. Inoue, T. and K. Kiyono (1988) ``Optimal Restriction on Foreign Trade and Investment with a Nontraded Good'', Economic Studies Quarterly, Vol. 39, pp. 246±257. ± 603 ± # Japanese Economic Association 2000. The Japanese Economic Review Jones, R. W. (1967) ``International Capital Movements and the Theory of Tariff and Trade: Comment'', Quarterly Journal of Economics, Vol. 81, pp. 1±38. Kemp, M. C. (1969) The Pure Theory of International Trade and Investment, Englewood Cliffs, NJ: Prentice-Hall. Woodland, A. D. (1982) International Trade and Resource Allocation, Amsterdam: North-Holland. ± 604 ± # Japanese Economic Association 2000.
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