duopoly supergames with product differentiation abstract when goods are complements or very close substitutes more tacit collusion is supported by trigger strategies in price setting supergames than in quantity setting supergames for moderate or poor substitutes the situation is reversed this contrasts with the static situation where price setting strategies always lead to higher welfare

lobbying by ethnic groups and aid allocation we develop a political economic model of foreign aid allocation each ethnic group in the donor country lobbies the government to allocate more aid to its country of origin and the government accepts political contributions from lobby groups initial per capita income of the recipients and those of the ethnic groups are shown to be important determinants of the solution of the political equilibrium we also examine the effects of changes in the degree of corruption aid fatigue and ethnic composition in the donor country on the allocation of aid

vertical antitrust policy as a problem of inference the legality of nonprice vertical practices in the u s is determined by their likely competitive effects an optimal enforcement rule combines evidence with theory to update prior beliefs and specifies a decision that minimizes the expected loss because the welfare effects of vertical practices are theoretically ambiguous optimal decisions depend heavily on prior beliefs which should be guided by empirical evidence empirically vertical restraints appear to reduce price and or increase output thus absent a good natural experiment to evaluate a particular restraint s effect an optimal policy places a heavy burden on plaintiffs to show that a restraint is anticompetitive

capacity constraints mergers and collusion abstract the objective of this paper is two fold to contribute to the analysis of tacit collusion in bertrand supergames with asymmetric capacity constraints and from a more applied perspective to bring a new light on merger analysis and provide useful guidelines for competition policy taking into account dynamic aspects of competition it is well known that capacity constraints affect tacit collusion as they limit both incentives to deviate e g to undercut rivals and retaliation possibilities however most studies have so far focused on symmetric situations where all firms have the same capacity which leads to ambiguous and unintuitive results and also considerably limits the scope of application studying asymmetric situations makes it possible to analyse the impact of changes in the distribution of these capacities expansions but also mergers split offs transfers etc and to provide guidelines for competition policy and particularly for merger policy these guidelines which differ substantially from those inspired by more static analyses such as the herfindahl or other standard concentration tests are applied to a famous merger that took place in the french bottled water market the nestle perrier merger case

are those paid more really more productive the case of experience this study uses computerized personnel microdata on the white male managerial and professional employees at a major u s corporation to address the following question can the additional earnings which are associated with more labor market experience at a point in time really be explained by higher productivity at the same point in time our answer to this question based on both cross sectional and longitudinal information is that performance plays a substantially smaller role in explaining cross sectional experience earnings differentials and earnings growth than is claimed by those who have adopted the human capital explanation of the experience earnings profile this response depends critically on our assumption that the performance ratings which supervisors give to their white male managerial and professional subordinates adequately reflect the subordinates relative productivity in the year of assessment we present a great deal of evidence which strongly supports this assumption

home biased gravity the role of migrant tastes in international trade abstract immigrants tend to buy products from their home countries as a result the more immigrants of a given ethnicity a country has the more it will tend to import from those immigrants countries of origin this effect of migrant heterogeneity is ignored by the standard gravity literature that assumes homogeneous preferences among resident consumers this paper embeds that observed regularity into a structural gravity model gravity derived from the almost ideal demand system generates bilateral trade shares with three distinct components ethnic composition of the resident population bilateral trade cost and per capita income using international trade and transnational migration data among 40 countries this paper estimates the home bias of each ethnic group in tastes the results show that consumers tastes for products from their country of origin deviate from unbiased levels by 35 percent on average ethnic taste bias is found to explain half of the trade bias counterfactuals suggest that anti immigration policy significantly impedes trade with immigrants countries of origin

migration and foreign aid when it comes to linkages between migration and the global allocation of foreign development assistance the size of the immigrant population from a recipient country residing in a donor country is an important determinant of dyadic aid commitments two complementary hypotheses probe this relationship first donors use foreign aid to achieve their broader immigration goals targeting migrant sending areas to increase development and decrease the demand for entry into the donor country second migrants already residing in the donor country mobilize to lobby for additional aid for their homeland empirical tests on a large sample of country pairs made up of twenty two donors and more than 150 recipients over the period 1993 to 2008 show robust support for these hypotheses

who benefits from aid for trade comparing the effects on recipient versus donor exports recent studies offer an ambiguous picture on the effectiveness of foreign aid in strengthening the export capacity of recipient countries moreover the literature on aid for trade aft has often neglected that exporters in the donor countries may be among the main beneficiaries we hypothesize that aft is as much in the self interest of donor countries as it may have promoted the exports of recipient countries we simultaneously estimate and compare the effects of aft on trade in both directions we find that aft increases recipient exports to donors as well as recipient imports from donors the first effect tends to dominate the latter which contradicts the skeptical view that donors grant aft primarily to promote their own export interests

corrupt governments do not receive more state to state aid governance and the delivery of foreign aid through non state actors abstract a core result of the aid allocation literature is that the quality of governance in recipient countries does not affect the amounts of foreign aid received donor countries may still give aid to poorly governed countries because of a dilemma they face those countries most in need typically also lack proper institutions this paper argues that donors try to resolve this dilemma by delivering aid through non state actors using aid shares as well as absolute amounts of aid allocated through state and non state channels and considering different dimensions of governance we provide evidence that bypassing governments via ngos and multilateral organizations is indeed a response to weak recipient state institutions the effect is stronger in aid sectors where donors can more easily switch between channels and weaker for higher levels of economic self interest among donors

vertical foreclosure with the choice of input specifications we develop an equilibrium model of vertical foreclosure with the choice of input specifications vertical foreclosure occurs as the upstream division of the integrated firm makes a specialized input for its sister downstream division while it would as an independent firm provide a generalized input the changes in incentives with vertical integration can be explained by the externalities the choice of a specialized input entails vertical integration allows the upstream firm to internalize the benefit of raising the rival firm s costs at the downstream level we derive conditions for equilibrium vertical foreclosure to occur and discuss its welfare consequences

exclusive territories and manufacturers collusion this paper highlights the rationale for exclusive territories in a model of repeated interaction between competing supply chains we show that with observable contracts exclusive territories have two countervailing effects on manufacturers incentives to sustain tacit collusion first granting local monopolies to retailers softens competition in a one shot game hence punishment profits are larger thereby rendering deviation more profitable second exclusive territories stifle deviation profits because retailers of competing brands adjust their prices to the wholesale contract offered by a deviant manufacturer whereas intrabrand competition prevents such instantaneous reaction we show that the latter effect tends to dominate thereby making exclusive territories a more suitable organizational mode to cooperate these insights are robust to endogenous communication between manufacturers we also consider retailers service investments here a novel effect emerges that softens the procollusive value of exclusive territories retailers of a deviant manufacturer increase investments which renders deviation more profitable this paper was accepted by preyas desai marketing

bertrand vs cournot competition in distribution channels with upstream collusion abstract this paper applies repeated game theory to tacit collusion in dynamic distribution channels based on the grim trigger strategy we examine competitors choice of the strategic instruments in distribution channels comprised of two manufacturers distributing through two independent retailers respectively first the paper discusses the upstream manufacturers collusion incentives under different competition modes for downstream retailers and shows that the manufacturers collusion incentives critically depend on the retailers competition modes and the discount factor we then identify the endogenous competition modes in equilibrium we find that upstream collusion is easier to sustain under cournot competition than bertrand competition and it is least likely to be sustained under mixed bertrand cournot competition furthermore in equilibrium retailers can engage in bertrand cournot or mixed bertrand cournot competition depending on the discount factor and the degree of product differentiation this study provides the rationale behind the emergence of various modes of competition in practical dynamic distribution channels especially the recent mixed bertrand cournot competition mode finally the manufacturers collusion incentives and retailers competition modes jointly affect the manufacturers profitability and social welfare we also discuss how the manufacturers profitability and social welfare vary under different competition modes taking upstream collusion into consideration we find that upstream collusion increases decreases social welfare for complements substitutes

multilateral resistance to migration the rate of migration observed between two countries does not depend solely on their relative attractiveness but also on the one of alternative destinations following the trade literature we term the influence exerted by other destinations on bilateral flows as multilateral resistance to migration and we show how it can be accounted for when estimating the determinants of migration rates in the context of a general individual random utility maximization model we propose the use of the common correlated effects estimator pesaran 2006 and apply it to high frequency data on the spanish immigration boom between 1997 and 2009 compared to more restrictive estimation strategies developed in the literature the bias goes in the expected direction we find a smaller effect of gdp per capita and a larger effect of migration policies on bilateral rates

wage discrimination against handicapped men and women the extent of discrimination against handicapped men and women is estimated in this paper observed wage differentials are corrected for selectivity bias the results indicate that almost one third of the wage differential for men and close to one half for women can be attributed to discrimination interestingly handicapped women are also subjected to sex discrimination

trade aid and migrations some basic policy issues the link between trade policy and international migration is explored using data from the united states and europe we conclude that restrictive trade policies in industrialised countries have most likely added to migration pressures we then turn to the broader question of the effects of income growth in the sending countries on the propensity to migrate we argue that in relatively poor countries an increase in income will be associated with higher migration flows for middle income countries however income growth will lead to lower migrations in the medium run therefore the relationship between development levels as measured by gdp per capita and the propensity to migrate follows an inverse u pattern econometric analysis of aggregate migration flows from southern europe provides considerable support for such conjecture excerpt

foreign assistance and emigration accounting for the role of non transferred aid since policymakers increasingly regard foreign aid as a means to manage international flows of migrants it is important to obtain accurate empirical evidence on the complex link between aid and migration recent research has shown that the impact of foreign assistance on migrant flows is highly heterogeneous across aid categories in this paper we focus on a dimension of heterogeneity that has so far not been considered in the literature namely whether or not the delivery of foreign aid is associated with a transfer of resources to the recipient country we show in a first step that non transferred aid is quantitatively important accounting for more than 25 of overall aid given by oecd dac donors in 2016 running separate gravity type regressions for transferred and non transferred aid we then find that transferred aid has a much stronger negative impact on migration than the previously used total aid variable that includes the non transferred component as may be expected non transferred aid itself does not appear to affect migrant flows a high share of non transferred aid would therefore be at odds with the donors stated goal of tackling the root causes of migration

a bargaining theory of distribution channels abstract a critical factor in channel relationships between manufacturers and retailers is the relative bargaining power of both parties in this article the authors develop a framework to examine bargaining between channel members and demonstrate that the bargaining process actually affects the degree of coordination and that two part tariffs will not be part of the market contract even in a simple one manufacturer one retailer channel to establish the institutional and theoretical bases for these results the authors relax the conventional assumption that the product being exchanged is completely specifiable in a contract they show that the institution of bargaining has force and it affects channel coordination when the complexity of nonspecifiability of the product exchange is present the authors find that greater retailer power promotes channel coordination thus there are conditions in which the presence of a powerful retailer might actually be beneficial to all channel members the authors rec

gender discrimination in the british labour market a reassessment survey wes the wes is the first british survey to collect detailed work histories and earnings data for a nationally representative sample of british women therefore for the first time estimates of discrimination based on real work experience data are presented a number of the earlier studies use data from the general household survey which does not collect actual work experience data they have been forced to use potential work experience or imputed experience in their wage equations this paper compares estimates based on potential or imputed experience with those based on actual experience using wes data our analysis finds that estimates of the parameters of a women s earnings function and a summary measure of gender discrimination using a measure of imputed experience differ little from those based on actual experience indeed our estimates of gender discrimination are very robust to estimation method and only slightly higher than miller s i987 estimate for i980 these estimates indicate that the oft quoted and influential study by zabalza and arrufat i 982 i 985 which pioneered the use of imputed experience severely underestimated the level of gender discrimination and exaggerated the impact

vertical integration raising rivals costs and upstream collusion abstract this paper analyzes the impact vertical integration has on upstream collusion when the price of the input is linear as a first step the paper derives the collusive equilibrium that requires the lowest discount factor in the infinitely repeated game when one firm is vertically integrated it turns out this is the joint profit maximum of the colluding firms the discount factor needed to sustain this equilibrium is then shown to be unambiguously lower than the one needed for collusion in the separated industry while the previous literature has found it difficult to reconcile raising rivals costs strategies following a vertical merger with equilibrium behavior in the static game they are subgame perfect in the repeated game studied here

vertical integration and downstream collusion we investigate the effect of a vertical merger on downstream firms ability to collude in a repeated game framework we show that a vertical merger has two main effects on the one hand it increases the total collusive profits increasing the stakes of collusion on the other hand it creates an asymmetry between the integrated firm and the unintegrated competitors the integrated firm accessing the input at marginal cost faces higher profits in the deviation phase and in the non cooperative equilibrium which potentially harms collusion as we show the optimal collusive profit sharing agreement takes care of the increased incentive to deviate of the integrated firm while optimal punishment erases the difficulty related to the asymmetries in the non cooperative state as a result vertical integration generally favors collusion

a practitioners guide to gravity models of international migration the use of bilateral data for the analysis of international migration is at the same time a blessing and a curse it is a blessing because the dyadic dimension of the data allows researchers to address a number of previously unanswered questions but it is also a curse for the various analytical challenges it gives rise to this paper presents the theoretical foundations of the estimation of gravity models of international migration and the main difficulties that have to be tackled in the econometric analysis such as the nature of migration data how to account for multilateral resistance to migration or endogeneity we also review some empirical evidence that has considered these issues

immigrant selection in the oecd in this paper we examine the determinants of educational selectivity in immigration using immigrant stock data for 70 source countries and 21 oecd destination countries as observed in the year 2000 2001 we develop a variant of the roy model to estimate the determinants of educational selectivity two key findings emerge first the effect of the skill premium which is at the core of the roy model can be observed only after we take into account the poverty constraints operating in the source countries second cultural similarities colonial legacies and physical distance are often more important determinants of educational selectivity than wage incentives or selective immigration policy

multimarket contact and collusive behavior traditional analyses of industrial behavior typically link the exercise of market power in an industry to internalfeatures such as demand conditions concentration and barriers to entry nevertheless some economists have remained concerned that external factors such as contact across markets may also play a significant role in determining the level of competitiveness in any particular industry in this article we examine the effect of multimarket contact on the degree of cooperation that firms can sustain in settings of repeated competition we isolate conditions under which multimarket contact facilitates collusion and show that these collusive gains are achieved through modes of behavior that have been identified in previous empirical studies of multimarketfirms

isolating the network effect of immigrants on trade within the migration trade nexus literature this paper proposes a more carefully defined measure of migration business networks and quantifies its impact on bilateral trade using cross sectional data and controlling for the overall bilateral stock of migrants the share of migrants employed in managerial business related occupations has a strong additional effect on trade those immigrants should be the ones directly involved in the diffusion and transmission of information relevant for companies trading with other countries their presence is found to increase the volume of trade especially of imports beyond the already known effect of immigrants or highly educated immigrants when we control for the presence of highly educated immigrants the share of immigrants in business network occupations shows a particularly large effect on trade in differentiated goods we also find that highly educated individuals in business related occupations are those contributing to stimulate import and export by the largest margin business network effects seem particularly important in stimulating exports to culturally different countries such as those with different language and legal origin

climatic factors as determinants of international migration we examine environmental change as a potential determinant of international migration we distinguish between unexpected short run factors captured by natural disasters as well as long run climate change and climate variability captured by deviations and volatilities of temperatures and rainfall from and around their long run averages starting from a simple neo classical model we use a panel dataset of bilateral migration flows for the period 1960 2000 that allows us to control for numerous time varying and time invariant factors we find no direct impact of climatic change on international migration across our entire sample these results are robust when conditioning on characteristics of origin countries as well as when further considering migrants returning home and the potential endogeneity of our network variable in contrast there is evidence of indirect effects of environmental factors going through wages we further find strong evidence that natural disasters beget greater flows of migrants to urban environs

labour market experience in female wage equations does the experience measure matter many studies have found estimated female wage and labour supply equations to be sensitive in some way to labour market experience although different studies yield different results and it seems there is still more to know about this key human capital variable this is especially so when separate information on individual womes s labour market experience is not available making it necessary to construct some measure of experience from other information this paper takes four such measures of labour market experience and investigates the effects of these upon the coefficients from an estimated wage equation as heckman s 1976 1979 two stage probit selection model is still widely used to test and correct for censoring bias the effect of different measures of experience upon the results from this procedure is also investigated

income maximization and the selection and sorting of international migrants abstract two prominent features of international labor movements are that the more educated are more likely to emigrate positive selection and more educated migrants are more likely to settle in destination countries with high rewards to skill positive sorting using data on emigrant stocks by schooling level and source country in oecd destinations we find that a simple model of income maximization can account for both phenomena results on selection show that migrants for a source destination pair are more educated relative to non migrants the larger is the absolute skill related difference in earnings between the destination country and the source results on sorting indicate that the relative stock of more educated migrants in a destination is increasing in the absolute earnings difference between high and low skilled workers we use our framework to compare alternative specifications of international migration estimate the magnitude of migration costs by source destination pair and assess the contribution of wage differences to how migrants sort themselves across destination countries

equilibrium vertical foreclosure the authors formulate a complete but analytically simple equilibrium model of vertical mergers to evaluate the logic of standard vertical foreclosure claims and the criticisms made of those claims the model includes incentives of the integrated firm and unintegrated input suppliers to exclude rivals and the potential holdout problem in this fully specified model vertical foreclosure can emerge in equilibrium copyright 1990 by american economic association

vertical mergers and market foreclosure ythe model in this paper illustrates three effects of vertical mergers when both stages are oligopolistic and vertically integrated and unintegrated producers coexist first the merging firm increases its final good output second the resulting backward shift in the residual demand curve facing unintegrated final good producers ylowers their demand for the intermediate good third the merged firm withdraws from the intermediate good market the increased concentration pushes the intermediate good price upward which effect dominates depends on market structure under some conditions a vertical merger causes the price of the final good to increase

25 years of aid allocation practice whither selectivity the 4p framework poverty population policy and proximity is introduced as a way of understanding a donor s aid allocation we use the two part model and examine the period 1982 2006 the results indicate that recent conclusions of increasing selectivity are misplaced for the seven major donors analyzed who together represent the majority of development aid indeed the effect of each of the commonly mentioned time trends selectivity the end of the cold war and the commencement of the global war on terror is much smaller than the role of donor heterogeneity which appears sizeable and entrenched

vertical integration as a source of hold up while vertical integration is traditionally seen as a solution to the hold up problem this article highlights instead that it can generate hold up problems for rivals we consider a successive duopoly where downstream firms invest and then secure support from an upstream supplier we first show that vertical integration generates ex ante incentives to create hold up problems an integrated supplier is willing to pre commit itself to appropriating or dissipating part of its customer s profits to expose the independent rival to being held up by the other supplier and discourage in this way the rival s investment we then show that even in the absence of any pre commitment vertical integration also creates hold up problems ex post when degrading the quality of the support provided to one downstream firm benefits its rival we also provide illustrations in terms of standard industrial organization models and of antitrust cases and discuss the robustness of the insights

incomplete contracts vertical integration and supply assurance this paper extends the analysis of transactions cost models of vertical integration to multilateral settings its main focus is on supply assurance concerns which arise when several downstream firms are competing for inputs in limited supply integration reduces supply assurance concerns for an integrating firm but it may increase them for others therefore to explain the scope of any firm one must consider the overall network of production and distribution relations three fundamental questions are addressed 1 what are the effects of different integration structures 2 what are the determinants of the socially efficient integration structures 3 in what way do equilibrium integration structures differ from socially efficient structures

incentives for input foreclosure we analyze the incentives of a vertically integrated firm to foreclose downstream rivals in contrast to the extant literature our model allows for upstream price competition between suppliers of only imperfectly substitutable inputs as the integrated firm decides on the degree of foreclosure through the scale of its continued participation in a merchant market the model can be applied also to cases where the foreclosed input is not essential as well as to cases where foreclosure is not complete we find that incentives to foreclose are much lower than in existing models with upstream cournot competition if there is also cournot competition downstream there will never be complete foreclosure in the case of linear demand potentially more important for practical purposes is our criticism of some explicit assertions made in the european commission s 2007 non horizontal merger guidelines we find that pre merger margins on the up and downstream markets are not necessarily good predictors of the incentives for subsequent i e post merger foreclosure

aid and migration substitutes or complements this paper investigates the impact of aid on migration and identifies two channels bilateral aid influences migration by enhancing the information about labor market conditions in the destination country attraction effect total aid correlates with migration through increasing expenditure financing and hence wages in countries of origin push effect we compute the critical level of income above which emigration and income are substitutes which is about us 7 300 per capita in ppp 2000 prices for example brazil or russia we argue that for countries below this threshold there is a trade off between aid and migration policies a tightening of the migration policy is equivalent to a reduction of the level of aid by about 24 a comparison of skilled and unskilled migrations shows that the former are more sensitive to the attraction effect than the latter

the impact of foreign aid on migration revisited abstract while policymakers hope to stem migration flows by giving foreign aid existing empirical evidence points in the opposite direction by loosening budget constraints aid tends to encourage people to emigrate in this paper we revisit the aid migration link using a substantially extended and adjusted econometric approach based on a gravity model of international migration in contrast to the previous literature we obtain evidence of a negative relationship between the total aid a country receives and emigration rates this even holds for the poorer part of recipient countries which suggests that the budgetary constraint channel does not play a significant role in shaping migration decisions the most plausible explanation for these contrasting results is that unlike in previous studies we use migrant flows rather than migrant stocks as the dependent variable in substantive terms the limited importance of the budgetary constraint channel might reflect that positive welfare effects of foreign aid tend to manifest themselves in improved public services for the poor rather than higher incomes which is in line with the reorientation of foreign aid towards social sectors under the millennium development goals

aid and growth what does the cross country evidence really show abstract we examine the effects of aid on growth in cross sectional and panel data after correcting for the possible bias that poorer or stronger growth may draw aid contributions to recipient co

do vertical mergers facilitate upstream collusion we investigate the impact of vertical mergers on upstream firms ability to collude when selling to downstream firms in a repeated game we show that vertical mergers give rise to an outlets effect the deviation profits of cheating unintegrated firms are reduced as these firms can no longer profitably sell to the downstream affiliates of their integrated rivals vertical mergers also result in an opposing punishment effect integrated firms typically make more profit in the punishment phase than unintegrated upstream firms the net result of these effects in an unintegrated industry is to facilitate upstream collusion we provide conditions under which further vertical integration also facilitates collusion

anticompetitive vertical integration by a dominant firm backward vertical integration by a dominant firm into an upstream competitive industry causes both input and output prices to rise the dominant firm s advantage may or may not offset the negative effect of higher prices on social welfare whether it does depends on a simple indicator derived from input and output market shares and the degree of prior vertical integration a vertical merger is similar to a hypothetical horizontal merger suggesting that vertical merger policy for this industry should be similar to horizontal merger policy the dominant firm model yields an observable sufficient indicator of welfare improving vertical mergers copyright 1998 by american economic association

out migration wealth constraints and the quality of local amenities the relation between income and migration intentions can be monotonically decreasing increasing or inverse u shaped dependent on the level of migration cost relative to wealth and if individuals are credit constrained using unique individual level data covering countries in three geographic regions sub saharan africa asia and latin america we show that migration intentions respond to individual wealth and that the pattern differs across the country groups studied in a manner compatible with the predictions of our simple model we also show that contentment with various dimensions of local amenities such as public services and security are key determinants of migration intentions

equilibrium vertical foreclosure reply in ordover saloner and salop 1990 hereafter oss we showed that a downstream duopolist may have an incentive to backward integrate in order to foreclose its downstream rival from a source of upstream supply as a result of the vertical integration the downstream rival s input price increases giving the integrating firm a competitive advantage in the downstream market moreover in equilibrium the foreclosed downstream rival does not find it profitable to negate these effects by integrating itself oss considers a four stage game involving two upstream firms ul and u2 and two downstream firms dl and d2 in the first stage the downstream firms can bid to acquire ul if there is an acquisition say dl acquires ul to form f1 upstream input prices are set in the second stage in the third stage knowing the input prices it faces d2 can attempt to acquire u2 finally in the fourth stage dl and d2 compete a la bertrand with differentiated products in his comment david reiffen 1992 makes three distinct points first he notes that once dl has acquired ul the equilibrium of the subsequent subgame depends critically on how upstream prices are set in the second stage he argues that our results depend on the ability of fl to commit to a high upstream price this criticism previously has been made by oliver hart and jean tirole 1990 we show below that the results in oss do not depend on the ability of fl to commit instead our main result stems from the fact that vertical integration changes the firm s incentives to engage in price cutting in the input market the notion that vertically integrated firms behave differently from unintegrated ones in supplying inputs to downstream rivals would strike a businessperson if not an economist as common sense 1 we show that there is theoretical merit to that common sense view second reiffen argues that the game considered by oss is similar to a game in which there is no vertical integration but rather where a nonintegrated dl has a first mover advantage in the downstream market in such a game dl benefits from the ability to commit to the price that its stackelberg leadership position gives it reiffen considers this to be additional evidence in support of the claim that oss depends critically on fl s ability to commit not on vertical integration we explain why the mechanism by which dl is able to raise its profits in the sequential one shot game considered by reiffen is conceptually quite different from the mechanism by which dl profits from vertical integration in oss third reiffen argues that our results depend on there being only two upstream firms this is correct in the symmetric bertrand model analyzed however as we discuss below our results do obtain as long as the upstream price is decreasing in the number of firms as occurs in many oligopoly models particularly when costs vary across firms the next section summarizes the conceptual problems pertaining to upstream pricing these problems are resolved in section ii by means of simple and natural price ordover department of economics new york university 269 mercer st 7th floor new york ny 10003 saloner graduate school of business stanford university stanford ca 94305 salop georgetown university law center 600 new jersey avenue nw washington dc 20001 we have benefited greatly from several discussions with faruk gul research support from the national science foundation grant 8813943 iri the sloan foundation and the c v starr center for applied economics at nyu is gratefully acknowledged for example the japan u s strategic impediments initiative is predicated on the proposition that the loosely linked japanese firms that form the various keiretsu do discriminate against nonaffiliated firms