Shares of Regeneron Pharmaceuticals Inc. REGN closed Tuesday's session down 1.70% to $731.77, marking a third consecutive day of losses for the biopharmaceutical company's stock. The underperformance occurred against a backdrop of broader market weakness, as the S&P 500 Index SPX fell 0.49% to close at 7,138.80 and the Dow Jones Industrial Average DJIA dipped 0.05% to 49,141.93. Despite the general downturn across the indices, Regeneron experienced a larger percentage decline compared to its competitors, distinguishing it as a relative underperformer within the sector for the day. The article notes that the broader market environment contributed significantly to the drop, with REGN being one of several stocks affected by what proved to be an all-around rough trading session. Data provided by FactSet indicates that real-time last sale data reflects trades reported through Nasdaq only, with intraday data potentially delayed at least 15 minutes or in accordance with specific exchange requirements. MarketWatch published this news on April 28, 2026, at 4:43 p.m. ET, emphasizing the stock's recent streak of negative performance that has continued for three straight days.