Investors holding shares of Amgen (AMGN), the $234 billion maker of drugs such as Repatha and Prolia, likely pair that position with broad exposure to the S&P 500. As the broader market rises and falls each day, the pharmaceutical stock’s individual performance blends with the rest of that capital. So when the market drops, does Amgen make your losses bigger?
Amgen Stock Lost Little On The Market’s Down Days
No. Over the past year to October 15, 2026, the S&P 500 lost 0.588% on its average down day, while a $10,000 holding in Amgen lost only about $15.90. On the index’s average up day, which posted a gain of 0.638%, Amgen added about $42.40 to that same holding. The stock captured about two-thirds of the broader market’s gains while absorbing only about a quarter of its losses.
This relative downside protection does not mean Amgen is a calm stock. Its volatility, or how far the price typically swings in a year, stood at 29.4% over the past year, compared with just 12.7% for the index. These sharp price swings did not track the broader market. For each 1% the index moved, Amgen moved only about 0.51% on average. Most of its swings were its own, so the stock added little to the market risk investors already carried.
This insulated pattern did not hold true every month. The S&P 500 fell 5.1% in March 2026, its weakest month of the past year. During that same stretch, a $10,000 holding in Amgen lost about $935. That 9.4% fall was close to twice the index’s decline. Over a bad month, Amgen can still add to your portfolio losses.
Will Amgen Keep Moving Apart From The Market?
It likely will. Amgen is a business in transition, and the news that matters most for it centers on its own drugs. In fiscal Q2 2026, sales of Prolia and XGEVA fell 33% from a year earlier. Management said it expected this drop following the launch of several biosimilar competitors, which are rival versions of those treatments. During that same quarter, the six drugs management calls its key growth drivers grew 26% together.
The company is also spending to scale up manufacturing for the launch of MariTide. It aims to make the treatment the first obesity therapy given monthly or less often. With that much riding on its own drugs, Amgen is likely to keep moving apart from the market, just as it did over the past year. During that time, the company’s daily moves lined up only loosely with the index’s, measuring 0.22 on a scale where 1 means moving in perfect step.
Has Amgen Paid You For Its Wider Swings?
