As one of the important aspect of a business, supply chain operations should be optimized by each firm within the industries. The complexity of supply chain is beyond measure, considering the number of firms involved in the competition and also another various effect, such as information asymmetry and competition asymmetry. This research try to introduce the concept of horizontal collaboration, which firms are collaborating with another firms in the same level. Collaboration in supply chain is difficult to conduct, this research took one of the simplest form of collaboration which is information sharing. Competition asymmetry is not a new thing for the supply chain, therefore, this research also considers this condition by utilizing the Stackelberg game. The results show that under information sharing firms earn greater profit compared to when they act individually. Number of participants in a collaboration would affect the individual profit of each participant.

Acs, Z. J., & Audretsch, D. B. (1987). Innovation, market structure, and firm size. The Review of Economics and Statistics, 69(4), 567-574.
Bahinipati, B. K., Kanda, A., & Deshmukh, S. (2009). Horizontal collaboration in semiconductor manufacturing industry supply chain: An evaluation of collaboration intensity index. Computers & Industrial Engineering, 57(3), 880-895.
Barratt, M. (2004). Understanding the meaning of collaboration in the supply chain. Supply Chain Management: An International Journal, 9(1), 30-42.
Berninghaus, S., Ehrhart, K.-M., & Güth, W. (2010). Strategische spiele: Eine einführung in die spieltheorie. Berlin: Springer-Verlag.
Bhaskaran, K., & Leung, Y. T. (1997). Manufacturing supply chain modelling and reengineering. Sadhana, 22(2), 165-187.
Bowersox, D. J., Closs, D. J., & Cooper, M. B. (2013). Supply chain logistics management (Vol. 2). New York: McGraw-Hill.
Chávez, H., Castillo-Villar, K. K., Herrera, L., & Bustos, A. (2016). Simulation-based multi-objective model for supply chains with disruptions in transportation. Robotics and Computer-Integrated Manufacturing, 43(2017), 39-49.
Cruijssen, F., Cools, M., & Dullaert, W. (2007). Horizontal cooperation in logistics: Opportunities and impediments. Transportation Research Part E: Logistics and Transportation Review, 43(2), 129-142.
Damanpour, F. (2010). An integration of research findings of effects of firm size and market competition on product and process innovations. British Journal of Management, 21(4), 996-1010.
Ding, H., Guo, B., & Liu, Z. (2011). Information sharing and profit allotment based on supply chain cooperation. International Journal of Production Economics, 133(1), 70-79.
Ellinger, A. E. (2000). Improving marketing/logistics cross-functional collaboration in the supply chain. Industrial Marketing Management, 29(1), 85-96.
Fan, T., Vigeant-Langlois, L., Geissler, C., Bosler, B., & Wilmking, J. (2001). Evolution of global airline strategic alliance and consolidation in the twenty-first century. Journal of Air Transport Management, 7(6), 349-360.
Fawcett, S. E., & Magnan, G. M. (2002). The rhetoric and reality of supply chain integration. International Journal of Physical Distribution & Logistics Management, 32(5), 339-361.
Fiala, P. (2005). Information sharing in supply chains. Omega, 33(5), 419-423.
Ganeshan, R., & Harrison, T. P. (1995). An introduction to supply chain management. Department of Management Sciences and Information Systems, 303.
Ha, A. Y., & Tong, S. (2008). Contracting and information sharing under supply chain competition. Management Science, 54(4), 701-715.
Ha, A. Y., Tong, S., & Zhang, H. (2011). Sharing demand information in competing supply chains with production diseconomies. Management Science, 57(3), 566-581.
Heifetz, A., & Yalon-Fortus, J. (2012). Game Theory: Interactive strategies in economics and management. United Kingdom: Cambridge University Press.
Horvath, L. (2001). Collaboration: The key to value creation in supply chain management. Supply Chain Management: An International Journal, 6(5), 205-207.
Kong, G., Rajagopalan, S., & Zhang, H. (2013). Revenue sharing and information leakage in a supply chain. Management Science, 59(3), 556-572.
Lambert, D. M., & Cooper, M. C. (2000). Issues in supply chain management. Industrial Marketing Management, 29(1), 65-83.
Lambert, D. M., Cooper, M. C., & Pagh, J. D. (1998). Supply chain management: implementation issues and research opportunities. The International Journal of Logistics Management, 9(2), 1-20.
Lee, H. L., Padmanabhan, V., & Whang, S. (1997). Information distortion in a supply chain: The bullwhip effect. Management Science, 43(4), 546-558.
Lee, H. L., & Whang, S. (2000). Information sharing in a supply chain. International Journal of Manufacturing Technology and Management, 1(1), 79-93.
Li, L. (2002). Information sharing in a supply chain with horizontal competition. Management Science, 48(9), 1196-1212.
Li, L. (2007). Supply chain management: Concepts, techniques and practices enhancing the value through collaboration. Singapore: World Scientific.
Li, S., Ragu-Nathan, B., Ragu-Nathan, T., & Rao, S. S. (2006). The impact of supply chain management practices on competitive advantage and organizational performance. Omega, 34(2), 107-124.
McCarthy, T. M., & Golicic, S. L. (2002). Implementing collaborative forecasting to improve supply chain performance. International Journal of Physical Distribution & Logistics Management, 32(6), 431-454.
McGuigan, J. R., & Moyer, R. C. (2013). Managerial economics: Applications, strategies, and tactics. Singapore: Nelson Education.
Mishra, B. K., Raghunathan, S., & Yue, X. (2007). Information sharing in supply chains: Incentives for information distortion. IIE Transactions, 39(9), 863-877.
Munson, C. L., & Rosenblatt, M. J. (2001). Coordinating a three-level supply chain with quantity discounts. IIE Transactions, 33(5), 371-384.
Myerson, R. B. (2013). Game theory. United States of America: Harvard University Press.
Nagarajan, M., & Sošić, G. (2008). Game-theoretic analysis of cooperation among supply chain agents: Review and extensions. European Journal of Operational Research, 187(3), 719-745.
Nakamura, T. (2015). One-leader and multiple-follower Stackelberg games with private information. Economics Letters, 127, 27-30.
Narus, J. A., & Anderson, J. C. (1996). Rethinking distribution: Adaptive channels. Harvard Business Review, 74(4), 112-120.
Neuman, J. v., & Morgenstern, O. (1953). Theory of games and economic behavior. Princeton: Princeton University Press.
Paulraj, A., Lado, A. A., & Chen, I. J. (2008). Inter-organizational communication as a relational competency: Antecedents and performance outcomes in collaborative buyer–supplier relationships. Journal of Operations Management, 26(1), 45-64.
Porter, M. (2001). The value chain and competitive advantage. Understanding Business: Processes, 50-66.
Raju, J. S., & Roy, A. (2000). Market information and firm performance. Management Science, 46(8), 1075-1084.
Ren, Z. J., Cohen, M. A., Ho, T. H., & Terwiesch, C. (2010). Information sharing in a long-term supply chain relationship: The role of customer review strategy. Operations Research, 58(1), 81-93.
Romp, G. (1997). Game theory: introduction and applications. United States: Oxford University Press.
Sabath, R. E., & Fontanella, J. (2002). The Unfulfilled Promise of Supply Chain Collaboration. Supply Chain Management Review, 6(4), 24-29.
Saenz, M. J., Ubaghs, E., & Cuevas, A. I. (2015). Enabling Horizontal Collaboration Through Continuous Relational Learning. United States: Springer.
Scherer, F. M., & Ross, D. (1990). Industrial market structure and economic performance. Boston: Houghton Mifflin Company Boston.
Seifert, D. (2003). Collaborative planning, forecasting, and replenishment: How to create a supply chain advantage. United States: AMACOM Div American Mgmt Assn.
Sheppard, E. J., & Seidman, D. (2001). Ocean shipping alliances: The wave of the future? International Journal of Maritime Economics, 3(4), 351-367.
Shin, H., & Tunca, T. I. (2010). Do firms invest in forecasting efficiently? The effect of competition on demand forecast investments and supply chain coordination. Operations Research, 58(6), 1592-1610.
Simatupang, T. M., & Sridharan, R. (2002). The collaborative supply chain. The International Journal of Logistics Management, 13(1), 15-30.
Simchi-Levi, D., Simchi-Levi, E., & Kaminsky, P. (1999). Designing and managing the supply chain: Concepts, strategies, and cases. New York: McGraw-Hill.
Songini, M. L. (2001). Supply chain ROI is Elusive. Computerworld, 35(1), 1.
Tang, O., & Musa, S. N. (2011). Identifying risk issues and research advancements in supply chain risk management. International Journal of Production Economics, 133(1), 25-34.
Tayur, S., Ganeshan, R., & Magazine, M. (2012). Quantitative models for supply chain management (Vol. 17). United States: Springer Science & Business Media.
Tsiakis, P., Shah, N., & Pantelides, C. C. (2001). Design of multi-echelon supply chain networks under demand uncertainty. Industrial & Engineering Chemistry Research, 40(16), 3585-3604.
Vives, X. (1984). Duopoly information equilibrium: Cournot and Bertrand. Journal of Economic Theory, 34(1), 71-94.
Von Stackelberg, H. (1952). The theory of the market economy. United Kingdom: Oxford University Press.
Wang, C. G., & Smith, K. (2016). China conference explored "supply chain management plus". CSCMP NOTEBOOK. Retrieved from CSCMP's Supply Chain Quarterly website: http://www.supplychainquarterly.com/departments/20160922-china-conference-explored-supply-chain-management-plus/
Webster, T. J. (2009). Introduction to game theory in business and economics. New York: ME Sharpe.
Yan, R., & Pei, Z. (2011). Information asymmetry, pricing strategy and firm's performance in the retailer-multi-channel manufacturer supply chain. Journal of Business Research, 64(4), 377-384.
Yue, D., & You, F. (2014). Game-theoretic modeling and optimization of multi-echelon supply chain design and operation under Stackelberg game and market equilibrium. Computers & Chemical Engineering, 71, 347-361.