23/28 Our study found that the manufacturer - the partner suffering from the asy f th- would always benefit (increased profit) with more information. We also found that, with information asymmetry, the direct channel price does not change, while the retailer enjoys higher price. One interesting finding is that the quantum of value-added does not change under any scenario and is only dependent on the retailer’s cost st ld enable the manufacturer to decide about an information sharing contract which would incl e optimum policy depend on the various market pe the base demand, and the migration parameter. Our results can be used as a guideline to set decisions about other variables, like product quality and return policy in order to influence these market parameters to move in the direction which would be beneficial to the channel partners. We also showed the benefit of the complete channel integration. Our model can be extended in many different directions. We could study a more complex demand function rather than the linear type used in our model. We can also let the manufacturer to do value added service, instead of the retailer. Appendix Proof of Proposition 1(a) ) )( 2 ( )) ( ( ) ( 1 2 2 2 2 1 1 2 2 1 1 r p v p a v p v p r p a p d c p d p v I + + - - + - + - = - + = η π Then we take first order condition with respect to p 1 , p 2 and v, and set them equal to zero, respectively. After that, solving these three equations simultaneously, we can get the desired result. Proof of Proposition 1(b) 2 _ _ 2 * * 2 ) 4 1 2 ( ) ( η η π π π + - = ⇒ = + - - = a L L d C w p R F R F v F R DOI: 10.3401/poms.1080.0069 Online Supplement for "Optimal Contract Design for Mixed Channels Under Information Asymmetry" by Samar K. Mukhopadhyay, Xiaowei Zhu, and Xiahang Yue