S&P Dow Jones Indices added Vylor to the S&P 500 immediately on Thursday, with Twilio scheduled to join before the market open on Tuesday.
Vylor, trading under the ticker VYLR on the New York Stock Exchange, is the seed and genetics business that Corteva recently spun off as a standalone company.
The index change took effect on the same day the separation between the two companies closed and regular-way trading in VYLR officially began.
Corteva, now the smaller post-spin entity, was deemed a better fit for the S&P MidCap 400, where it will land before the open on October 6.
Shares of Vylor edged up 3% in after-hours trading Thursday after the announcement, while Twilio gained 1.2% in the same session.
Index inclusion forces passive funds and ETFs that track the S&P 500 to purchase the newly added stocks, which typically drives near-term price appreciation.
Twilio, the cloud software company trading under the ticker TWLO, will take the S&P 500 seat being vacated by Warner Bros. Discovery ahead of that company’s pending acquisition by Paramount Skydance.
Warner Bros. Discovery is being removed from the index in connection with the merger, after which Paramount Skydance plans to switch its primary listing to the New York Stock Exchange.
Twilio had been a constituent of the S&P MidCap 400 since August 2025 before earning its promotion to the large-cap benchmark.
The reshuffle creates a cascade of index changes across multiple tiers, with several other companies moving up or down the index ladder as a result.
Corteva replaces Olin (OLN) in the MidCap 400, while FormFactor (FORM) moves up from the SmallCap 600 to fill the MidCap 400 spot that Twilio is vacating.
Workiva (WK) will replace FormFactor in the S&P SmallCap 600, rounding out a broad set of changes that span all three major S&P index tiers.
All of the changes beyond Vylor’s immediate addition are scheduled to take effect before the market open on Tuesday, giving funds time to rebalance their portfolios accordingly.
