Wells Fargo analyst David Maris attributes today's weakness in shares of generic drugmakers Teva (TEVA) and Mylan (MYL) to the low sales multiple at which Novartis' (NVS) Sandoz unit is selling a portfolio of generic and branded products to Aurobindo. While Teva and Mylan clearly have very different businesses than the largely commodity and dermatology portfolio Sandoz is selling for $900M, Maris believes some investors are looking at the deal as a proxy for what the commodity portions of their U.S. businesses might be worth, he tells investors. Maris, who has previously voiced caution about generics and generic drug pricing, sees Novartis' deal as another indication that the environment remains challenging.