After surging above $20 on news that a competitors drug approval was delayed, Relypsa (RLYP) has seen the stock trend sideways. What originally started as positive news with the delay of FDA approval of AstraZeneca's (AZN) ZS-9, has now turned to mostly neutral with the eventual approval of the drug expected to occur in the next year or so. Notable bear Andrew Berens of Morgan Stanley actually switched back to an underweight with a price target of $9 on Relypsa. The stock now trades for $19 suggesting plenty of downside if the analyst is correct. His basic theory agrees with our summary that the manufacturing concerns would eventually get worked out. In that regards, Valtessa would see limited long-term benefits from the delayed approval. Berens though sees AstraZeneca getting rapid FDA approval in possibly 4 to 6 months and taking 80% market share. Do you agree that ZS-9 gets approved this year? Will Relypsa lose 50% of its value? Disclosure: No position.