Stifel analyst, Paul Matteis says Sage Therapeutics (SAGE) shares below $50 represent one of the best opportunities in Stifel's coverage universe. The bear case is the uncertain path forward for SAGE-217, along with Zulresso looking commercially unviable, while Sage's cash burn profile seeming "misaligned" with the post-MOUNTAIN trial market capitalization, Matteis tells investors in a research note.

However, the analyst, who doesn't even completely disagree with the bear case, believes the stock "seems to heavily discount two major upside levers." SAGE-217 is a single positive acute major depressive disorder study away from being just as big of a drug as investors have always hoped, and SAGE-217's value in postpartum depression is underappreciated, even if another study is needed, contends the analyst. Matteis keeps a Buy rating on Sage Therapeutics with a $143 price target. The stock closed Friday down 10%, or $5.01, to $47.00.