Corteva completed the separation of its seed and seed technology operations into Vylor, a standalone company, sending Corteva shares down 84% to $12.57 from Wednesday's $77.65 close. The drop reflected the planned spinoff (corporate separation of a business), not a collapse in the company's operations. Vylor began trading Thursday and finished at $68.26. Because shareholders received one Vylor share for each Corteva share they owned, the combined value of their holdings was approximately $81, modestly above the prior $77.65 baseline. Vylor contains the larger former business, which generated approximately $10 billion in 2025 revenue and $3 billion in EBITDA (earnings before interest, taxes, depreciation and amortization). Corteva retained crop protection operations, including herbicides and insecticides, which produced $7.5 billion in sales and $1.4 billion in EBITDA during the same period. The seed business has historically delivered more consistent earnings growth than the chemical segment. Corteva had a market capitalization of approximately $52 billion before the separation, with most of that valuation transferring to Vylor. Oppenheimer analyst Kristen Owen said Corteva appeared undervalued below $12, valuing it at roughly six to seven times projected EBITDA, which she described as a floor-level valuation. Vylor traded at approximately 15 times EBITDA during its first session. The transaction also reshapes major U.S. equity indexes. Before markets open on Oct. 6, Vylor will take Corteva's former position in the S&P 500, while Corteva moves to the S&P MidCap 400. Vylor will be classified in consumer staples and Corteva will remain in materials. Twilio will join the S&P 500 at the same time, filling the vacancy created by Warner Bros. Discovery as its acquisition by Paramount Skydance approaches completion on Oct. 6. Twilio rose 3% in after-hours trading Thursday and has gained more than 100% year-to-date. Other index changes include FormFactor moving to the MidCap 400, Workiva entering the SmallCap 600, and Olin moving down to the SmallCap 600. Olin's move replaces Qorvo, which is being acquired by S&P 500 constituent Skyworks Solutions. Index-tracking portfolios face substantial rebalancing activity this week.