Suppose Homer and Smithers are in the same health insurance pool and they pay the same premium for their health insurance. Suppose further, that the SNPP discriminates against employees on the basis of body weight so that a negative wage penalty is associated with obesity. Finally, suppose Homer eschews exercise and loves jelly donuts much more than Smithers does. As a result, Homer also has much higher expected medical expenditures.

Does Homer impose a negative externality on Smithers? Explain why or why not, and describe carefully any assumptions you need to answer this question.