10 Best Performing S&P 500 Stocks So Far in 2026

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6. Keysight Technologies Inc. (NYSE:KEYS)

Year-to-Date Performance: 67.11%

Keysight Technologies Inc. (NYSE:KEYS) is one of the best performing S&P 500 stocks so far in 2026. On March 25, Keysight introduced two new receiver compliance test solutions designed to secure the reliability of high-speed in-vehicle networks. These tools support the industry’s shift toward software-defined vehicles and zonal architectures by enabling rigorous validation across a spectrum of speeds, from 10BASE-T1S up to 10GBASE-T1.

As data-intensive applications grow, these solutions address the mission-critical need for receiver/Rx testing to ensure safety-standard communication within the vehicle. The first of these innovations is the 10BASE-T1S Receiver Test Solution, developed in partnership with BitifEye Digital Test Solutions. It provides automated compliance software specifically for multi-drop Ethernet architectures, allowing engineers to verify signal integrity under harsh conditions like coupled noise and impaired channels.

Additionally, Keysight Technologies Inc. (NYSE:KEYS) debuted its nGBASE-AU Optical Automotive Ethernet testbed, which focuses on the high-bandwidth and EMI-resilient requirements of future platforms. Fully compliant with IEEE 802.3cz standards, this optical solution includes an advanced measurement suite for assessing signal quality in long-reach communications.

Keysight Technologies Inc. (NYSE:KEYS) is a leading American company providing electronic design, emulation, and test solutions to support innovation in the communications, aerospace, defense, automotive, semiconductor, and general electronics markets.

While we acknowledge the potential of KEYS to grow, our conviction lies in the belief that some AI stocks hold greater promise for delivering higher returns and have limited downside risk. If you are looking for an AI stock that is more promising than KEYS and that has 100x upside potential, check out our report about the cheapest AI stock.

Click to continue reading and see the 5 Best Performing S&P 500 Stocks So Far in 2026.

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