How Much Upside Is Left In Regeneron Stock?

Regeneron Pharmaceuticals (REGN) stock returned 37.9% in the year to October 16, 2026. This easily outpaced the 16.2% gain for the S&P 500 and left investors looking at a higher price. The underlying business has grown faster lately, yet its operating margin has slipped in each of the past three years. If you buy or hold the shares today, what could three more years of owning them make you.