Trade Desk's stock jumps on S&P 500 inclusion as Ansys exits index due to acquisition

In a significant market move, shares of The Trade Desk surged by 14% in after-hours trading on Monday as the digital advertising firm prepares to join the prestigious S&P 500 index. S&P Global made the announcement that Trade Desk will replace software company Ansys, effective this Friday. This change comes on the heels of Synopsys, which announced it has received the necessary regulatory approvals to proceed with its $35 billion acquisition of Ansys, a deal that was revealed last year and is expected to finalize around Thursday. Last week, the S&P 500 saw another adjustment as Datadog took over Juniper Networks' spot during the index's routine rebalancing. Typically, these adjustments are made during scheduled rebalancing; however, acquisitions can lead to unscheduled removals and replacements. Despite facing a tough year with a 36% decline in market value in 2025, Trade Desk's stock had previously experienced a remarkable rise of 63% in 2022 and 61% in 2023. The inclusion in a major index often triggers a rally, as portfolio managers adjust their holdings accordingly. With its current market cap at $37 billion, Trade Desk is positioned comfortably within the S&P 500’s average valuation. Founded in 2009 by CEO Jeff Green and David Pickles, the company made its public debut on the Nasdaq in 2016. Headquartered in Ventura, California, Trade Desk employs over 3,522 individuals and competes with giants like Amazon and Google.