U.S. Weekly Review | Teradyne Spikes 26%; Western Digital Surges 16%; Regeneron Rallies 13%; First Solar Jumps 10%; Seagate Rises 9%

This week, which stocks lagged or dragged? Weekly Winners column keeps up with market trends, helping Tigers sort out the week's hottest sectors, stock winners and important news.

Below are top 10 S&P 500 stock gainers for the week ended Oct. 31:

Teradyne Stock Spikes 26% on Earnings as AI Is Lifting Shares

Shares of Teradyne rose 26% this week after the maker of test systems for semiconductors and robotics beat quarterly earnings expectations and issued a blockbuster outlook.

The company posted adjusted earnings of 85 cents a share for the third quarter, ahead of Wall Street's call for 79 cents. Revenue totaled $769 million, up from $737 million a year ago and above analysts' consensus estimate of $744 million.

More importantly, Teradyne's fourth-quarter guidance blew past investors' expectations. The company anticipates revenue between $920 million and $1 billion for the current quarter, much higher than the $816 million analysts had forecast.

Western Digital Surges 16% After Forecasting Strong Quarterly Earnings

Western Digital forecast second-quarter earnings above Wall Street estimates on Thursday, betting on higher demand for its data storage products as cloud providers increase data center capacity. The company also increased the quarterly cash dividend on its common stock by 25% to $0.125 per share.

Data storage solutions firms, such as Western Digital and Seagate Technology, are benefiting from massive demand for high-capacity hard disk drives.

This surge is fueled by the AI boom and expanding cloud infrastructure, as cloud providers rely on these devices to store the vast amount of data required to train AI models.

Regeneron Tops Quarterly Estimates, Plans to Resubmit Eylea Application

Regeneron Pharmaceuticals beat Wall Street estimates for third-quarter results on Tuesday, helped by strong demand for its eczema treatment, Dupixent, and cancer treatment Libtayo. Shares of Regeneron surged 13% this week.

The drugmaker also announced plans to resubmit the marketing application for the pre-filled syringe version of higher-dose Eylea, or Eylea HD, after the U.S. Food and Drug Administration declined its approval on Monday.

The company has been facing multiple regulatory setbacks due to the issues at Catalent's Indiana filling facility, now owned by Novo Holdings, which led delays in three pending FDA applications for the eye drug Eylea.

First Solar Sales Top Estimates, Company to Open Another US Factory

First Solar, the biggest U.S.-based solar panel maker, beat expectations for third-quarter sales on Thursday, driven by robust demand for its products. Shares of First Solar soared over 10% this week.

Solar-generated electricity is one of the fastest-growing segments of the U.S. energy industry, driven by strong demand from corporations and governments to adopt cleaner sources of power and combat climate change.

First Solar said it would establish a new 3.7 GW manufacturing facility in the U.S., with production expected to start at the end of 2026 and ramp up through the first half of 2027.

Seagate Stock Pops 9% on Earnings. “Solid Execution, No Doubt,” Wall Street Says

Shares of Seagate Technology Holdings climbed 9% this week after the maker of data storage equipment breezed past quarterly earnings expectations and forecast another strong quarter. The stock was the top gainer in the S&P 500 Wednesday and was on pace for an all-time closing high, according to Dow Jones Market Data.

Seagate posted adjusted earnings of $2.61 a share for its fiscal first quarter, surpassing analysts' consensus call for $2.40. Revenue totaled $2.63 billion, up 21% from the prior year and above Wall Street's estimate of $2.55 billion.

The company also forecast revenue of $2.7 billion, plus or minus $100 million, for its fiscal second quarter. Analysts had expected $2.67 billion, per FactSet.