S&P 500’s Weakest Performer Struggles to Escape Selling ‘Vortex’

Trade Desk Inc. investors who stuck with the stock through a 15-month selloff that has left it down more than 80% will likely be waiting awhile for a rebound — if one ever materializes.

Since the start of 2025, the advertising-technology company’s shares are by far the worst performers in the S&P 500 Index, closing Friday at their lowest level since 2020 before staging a bit of a rebound this week. The rout has wiped out over $47 billion in market value. Shares were up 0.2% Wednesday.