The downgrade from Neutral to Sell by a significant analyst firm like B. Riley Securities suggests a bearish outlook on Madrigal Pharmaceuticals. The setting of a price target at $155, while not explicitly stated whether it's above or below the current trading price, typically indicates the analyst's expectation of where the stock will move in the short term. Given the downgrade, this could lead to negative sentiment among investors and potential downward pressure on the stock price.