S&P MidCap 400 index news
Every official S&P MidCap 400 change we track, newest first: the provider's announcement, the day it takes effect, and the press coverage around it. Each entry links to the newsroom where the original release is published.
Official sources
- Aug 20, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: Sun Communities (SUI) to join
S&P Dow Jones Indices announced on Aug 20, 2026 that Sun Communities will join the S&P MidCap 400, replacing Webster Bank. Effective after the close on Aug 20, 2026.
- Aug 20, 2026EffectiveS&P MidCap 400
S&P MidCap 400: SUI inclusion effective
Sun Communities entered the S&P MidCap 400 after the close on Aug 20, 2026, forcing every tracking fund to hold it.
- Jul 24, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: Krystal Biotech (KRYS) to join
S&P Dow Jones Indices announced on Jul 24, 2026 that Krystal Biotech will join the S&P MidCap 400, replacing Taylor Morrison. Effective after the close on Jul 24, 2026.
- Jul 24, 2026EffectiveS&P MidCap 400
S&P MidCap 400: KRYS inclusion effective
Krystal Biotech entered the S&P MidCap 400 after the close on Jul 24, 2026, forcing every tracking fund to hold it.
- Jul 22, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: Molina Healthcare (MOH) to join
S&P Dow Jones Indices announced on Jul 22, 2026 that Molina Healthcare will join the S&P MidCap 400, replacing National Storage Affiliates Trust. Effective after the close on Jul 22, 2026.
- Jul 22, 2026EffectiveS&P MidCap 400
S&P MidCap 400: MOH inclusion effective
Molina Healthcare entered the S&P MidCap 400 after the close on Jul 22, 2026, forcing every tracking fund to hold it.
- Jul 17, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: BrightSpring Health Services (BTSG) to join
S&P Dow Jones Indices announced on Jul 17, 2026 that BrightSpring Health Services will join the S&P MidCap 400, replacing Chart Industries. Effective after the close on Jul 17, 2026.
- Jul 17, 2026EffectiveS&P MidCap 400
S&P MidCap 400: BTSG inclusion effective
BrightSpring Health Services entered the S&P MidCap 400 after the close on Jul 17, 2026, forcing every tracking fund to hold it.
- Jul 6, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: Allison Transmission (ALSN) to join
S&P Dow Jones Indices announced on Jul 6, 2026 that Allison Transmission will join the S&P MidCap 400, replacing Goodyear Tire & Rubber. Effective after the close on Jul 6, 2026.
- Jul 6, 2026EffectiveS&P MidCap 400
S&P MidCap 400: ALSN inclusion effective
Allison Transmission entered the S&P MidCap 400 after the close on Jul 6, 2026, forcing every tracking fund to hold it.
- Jul 1, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: Toast, Inc. (TOST) to join
S&P Dow Jones Indices announced on Jul 1, 2026 that Toast, Inc. will join the S&P MidCap 400, replacing TopBuild Corp.. Effective after the close on Jul 1, 2026.
- Jul 1, 2026EffectiveS&P MidCap 400
S&P MidCap 400: TOST inclusion effective
Toast, Inc. entered the S&P MidCap 400 after the close on Jul 1, 2026, forcing every tracking fund to hold it.
- Jul 1, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: IES Holdings (IESC) to join
S&P Dow Jones Indices announced on Jul 1, 2026 that IES Holdings will join the S&P MidCap 400, replacing Janus Henderson. Effective after the close on Jul 1, 2026.
- Jul 1, 2026EffectiveS&P MidCap 400
S&P MidCap 400: IESC inclusion effective
IES Holdings entered the S&P MidCap 400 after the close on Jul 1, 2026, forcing every tracking fund to hold it.
- Jun 22, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: Roku, Inc. (ROKU) to join
S&P Dow Jones Indices announced on Jun 22, 2026 that Roku, Inc. will join the S&P MidCap 400, replacing Flex Ltd.. Effective after the close on Jun 22, 2026.
- Jun 22, 2026EffectiveS&P MidCap 400
S&P MidCap 400: ROKU inclusion effective
Roku, Inc. entered the S&P MidCap 400 after the close on Jun 22, 2026, forcing every tracking fund to hold it.
- Jun 22, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: Semtech (SMTC) to join
S&P Dow Jones Indices announced on Jun 22, 2026 that Semtech will join the S&P MidCap 400, replacing Coty. Effective after the close on Jun 22, 2026.
- Jun 22, 2026EffectiveS&P MidCap 400
S&P MidCap 400: SMTC inclusion effective
Semtech entered the S&P MidCap 400 after the close on Jun 22, 2026, forcing every tracking fund to hold it.
- Jun 22, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: Viavi Solutions (VIAV) to join
S&P Dow Jones Indices announced on Jun 22, 2026 that Viavi Solutions will join the S&P MidCap 400, replacing Blackbaud. Effective after the close on Jun 22, 2026.
- Jun 22, 2026EffectiveS&P MidCap 400
S&P MidCap 400: VIAV inclusion effective
Viavi Solutions entered the S&P MidCap 400 after the close on Jun 22, 2026, forcing every tracking fund to hold it.
- Jun 22, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: Sanmina Corporation (SANM) to join
S&P Dow Jones Indices announced on Jun 22, 2026 that Sanmina Corporation will join the S&P MidCap 400, replacing Concentrix. Effective after the close on Jun 22, 2026.
- Jun 22, 2026EffectiveS&P MidCap 400
S&P MidCap 400: SANM inclusion effective
Sanmina Corporation entered the S&P MidCap 400 after the close on Jun 22, 2026, forcing every tracking fund to hold it.
- Jun 22, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: Coeur Mining (CDE) to join
S&P Dow Jones Indices announced on Jun 22, 2026 that Coeur Mining will join the S&P MidCap 400, replacing BellRing Brands. Effective after the close on Jun 22, 2026.
- Jun 22, 2026EffectiveS&P MidCap 400
S&P MidCap 400: CDE inclusion effective
Coeur Mining entered the S&P MidCap 400 after the close on Jun 22, 2026, forcing every tracking fund to hold it.
- Jun 11, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: SiriusXM (SIRI) to join
S&P Dow Jones Indices announced on Jun 11, 2026 that SiriusXM will join the S&P MidCap 400, replacing Masimo. Effective after the close on Jun 11, 2026.
- Jun 11, 2026EffectiveS&P MidCap 400
S&P MidCap 400: SIRI inclusion effective
SiriusXM entered the S&P MidCap 400 after the close on Jun 11, 2026, forcing every tracking fund to hold it.
- May 18, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: SharkNinja (SN) to join
S&P Dow Jones Indices announced on May 18, 2026 that SharkNinja will join the S&P MidCap 400, replacing Flowers Foods. Effective after the close on May 18, 2026.
- May 18, 2026EffectiveS&P MidCap 400
S&P MidCap 400: SN inclusion effective
SharkNinja entered the S&P MidCap 400 after the close on May 18, 2026, forcing every tracking fund to hold it.
- Apr 9, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: DigitalOcean (DOCN) to join
S&P Dow Jones Indices announced on Apr 9, 2026 that DigitalOcean will join the S&P MidCap 400, replacing Casey's. Effective after the close on Apr 9, 2026.
- Apr 9, 2026EffectiveS&P MidCap 400
S&P MidCap 400: DOCN inclusion effective
DigitalOcean entered the S&P MidCap 400 after the close on Apr 9, 2026, forcing every tracking fund to hold it.
- Mar 23, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: Vicor Corporation (VICR) to join
S&P Dow Jones Indices announced on Mar 23, 2026 that Vicor Corporation will join the S&P MidCap 400, replacing ASGN Inc.. Effective after the close on Mar 23, 2026.
- Mar 23, 2026EffectiveS&P MidCap 400
S&P MidCap 400: VICR inclusion effective
Vicor Corporation entered the S&P MidCap 400 after the close on Mar 23, 2026, forcing every tracking fund to hold it.
- Mar 23, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: InterDigital (IDCC) to join
S&P Dow Jones Indices announced on Mar 23, 2026 that InterDigital will join the S&P MidCap 400, replacing ZoomInfo. Effective after the close on Mar 23, 2026.
- Mar 23, 2026EffectiveS&P MidCap 400
S&P MidCap 400: IDCC inclusion effective
InterDigital entered the S&P MidCap 400 after the close on Mar 23, 2026, forcing every tracking fund to hold it.
- Mar 23, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: Solstice Advanced Materials (SOLS) to join
S&P Dow Jones Indices announced on Mar 23, 2026 that Solstice Advanced Materials will join the S&P MidCap 400, replacing Lumentum. Effective after the close on Mar 23, 2026.
- Mar 23, 2026EffectiveS&P MidCap 400
S&P MidCap 400: SOLS inclusion effective
Solstice Advanced Materials entered the S&P MidCap 400 after the close on Mar 23, 2026, forcing every tracking fund to hold it.
- Mar 23, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: SiTime (SITM) to join
S&P Dow Jones Indices announced on Mar 23, 2026 that SiTime will join the S&P MidCap 400, replacing Coherent Corp.. Effective after the close on Mar 23, 2026.
- Mar 23, 2026EffectiveS&P MidCap 400
S&P MidCap 400: SITM inclusion effective
SiTime entered the S&P MidCap 400 after the close on Mar 23, 2026, forcing every tracking fund to hold it.
- Mar 23, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: CareTrust REIT (CTRE) to join
S&P Dow Jones Indices announced on Mar 23, 2026 that CareTrust REIT will join the S&P MidCap 400, replacing Kemper Corporation. Effective after the close on Mar 23, 2026.
- Mar 23, 2026EffectiveS&P MidCap 400
S&P MidCap 400: CTRE inclusion effective
CareTrust REIT entered the S&P MidCap 400 after the close on Mar 23, 2026, forcing every tracking fund to hold it.
- Mar 23, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: Moog Inc. (MOG.A) to join
S&P Dow Jones Indices announced on Mar 23, 2026 that Moog Inc. will join the S&P MidCap 400, replacing EchoStar. Effective after the close on Mar 23, 2026.
- Mar 23, 2026EffectiveS&P MidCap 400
S&P MidCap 400: MOG.A inclusion effective
Moog Inc. entered the S&P MidCap 400 after the close on Mar 23, 2026, forcing every tracking fund to hold it.
- Feb 9, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: Arrowhead Pharmaceuticals (ARWR) to join
S&P Dow Jones Indices announced on Feb 9, 2026 that Arrowhead Pharmaceuticals will join the S&P MidCap 400, replacing Ciena. Effective after the close on Feb 9, 2026.
- Feb 9, 2026EffectiveS&P MidCap 400
S&P MidCap 400: ARWR inclusion effective
Arrowhead Pharmaceuticals entered the S&P MidCap 400 after the close on Feb 9, 2026, forcing every tracking fund to hold it.
- Feb 2, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: Advanced Energy (AEIS) to join
S&P Dow Jones Indices announced on Feb 2, 2026 that Advanced Energy will join the S&P MidCap 400, replacing Comerica. Effective after the close on Feb 2, 2026.
- Feb 2, 2026EffectiveS&P MidCap 400
S&P MidCap 400: AEIS inclusion effective
Advanced Energy entered the S&P MidCap 400 after the close on Feb 2, 2026, forcing every tracking fund to hold it.
- Feb 2, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: Dutch Bros Inc. (BROS) to join
S&P Dow Jones Indices announced on Feb 2, 2026 that Dutch Bros Inc. will join the S&P MidCap 400, replacing PotlatchDeltic. Effective after the close on Feb 2, 2026.
- Feb 2, 2026EffectiveS&P MidCap 400
S&P MidCap 400: BROS inclusion effective
Dutch Bros Inc. entered the S&P MidCap 400 after the close on Feb 2, 2026, forcing every tracking fund to hold it.
- Feb 2, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: American Healthcare REIT (AHR) to join
S&P Dow Jones Indices announced on Feb 2, 2026 that American Healthcare REIT will join the S&P MidCap 400, replacing Cadence Bank. Effective after the close on Feb 2, 2026.
- Feb 2, 2026EffectiveS&P MidCap 400
S&P MidCap 400: AHR inclusion effective
American Healthcare REIT entered the S&P MidCap 400 after the close on Feb 2, 2026, forcing every tracking fund to hold it.
- Jan 30, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: TTM Technologies (TTMI) to join
S&P Dow Jones Indices announced on Jan 30, 2026 that TTM Technologies will join the S&P MidCap 400, replacing Civitas Resources. Effective after the close on Jan 30, 2026.
- Jan 30, 2026EffectiveS&P MidCap 400
S&P MidCap 400: TTMI inclusion effective
TTM Technologies entered the S&P MidCap 400 after the close on Jan 30, 2026, forcing every tracking fund to hold it.
- Jan 22, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: StandardAero (SARO) to join
S&P Dow Jones Indices announced on Jan 22, 2026 that StandardAero will join the S&P MidCap 400, replacing Frontier Communications. Effective after the close on Jan 22, 2026.
- Jan 22, 2026EffectiveS&P MidCap 400
S&P MidCap 400: SARO inclusion effective
StandardAero entered the S&P MidCap 400 after the close on Jan 22, 2026, forcing every tracking fund to hold it.
- Jan 2, 2026AnnouncementS&P MidCap 400
S&P MidCap 400: UiPath (PATH) to join
S&P Dow Jones Indices announced on Jan 2, 2026 that UiPath will join the S&P MidCap 400, replacing Synovus. Effective after the close on Jan 2, 2026.
- Jan 2, 2026EffectiveS&P MidCap 400
S&P MidCap 400: PATH inclusion effective
UiPath entered the S&P MidCap 400 after the close on Jan 2, 2026, forcing every tracking fund to hold it.
- Dec 22, 2025AnnouncementS&P MidCap 400
S&P MidCap 400: UL Solutions (ULS) to join
S&P Dow Jones Indices announced on Dec 22, 2025 that UL Solutions will join the S&P MidCap 400, replacing Comfort Systems USA. Effective after the close on Dec 22, 2025.
- Dec 22, 2025EffectiveS&P MidCap 400
S&P MidCap 400: ULS inclusion effective
UL Solutions entered the S&P MidCap 400 after the close on Dec 22, 2025, forcing every tracking fund to hold it.
- Dec 22, 2025AnnouncementS&P MidCap 400
S&P MidCap 400: Booz Allen Hamilton (BAH) to join
S&P Dow Jones Indices announced on Dec 22, 2025 that Booz Allen Hamilton will join the S&P MidCap 400, replacing Power Integrations. Effective after the close on Dec 22, 2025.
- Dec 22, 2025EffectiveS&P MidCap 400
S&P MidCap 400: BAH inclusion effective
Booz Allen Hamilton entered the S&P MidCap 400 after the close on Dec 22, 2025, forcing every tracking fund to hold it.
- Dec 22, 2025AnnouncementS&P MidCap 400
S&P MidCap 400: Hecla Mining (HL) to join
S&P Dow Jones Indices announced on Dec 22, 2025 that Hecla Mining will join the S&P MidCap 400, replacing Insperity. Effective after the close on Dec 22, 2025.
- Dec 22, 2025EffectiveS&P MidCap 400
S&P MidCap 400: HL inclusion effective
Hecla Mining entered the S&P MidCap 400 after the close on Dec 22, 2025, forcing every tracking fund to hold it.
- Dec 22, 2025AnnouncementS&P MidCap 400
S&P MidCap 400: Dycom Industries (DY) to join
S&P Dow Jones Indices announced on Dec 22, 2025 that Dycom Industries will join the S&P MidCap 400, replacing Iridium Communications. Effective after the close on Dec 22, 2025.
- Dec 22, 2025EffectiveS&P MidCap 400
S&P MidCap 400: DY inclusion effective
Dycom Industries entered the S&P MidCap 400 after the close on Dec 22, 2025, forcing every tracking fund to hold it.
- Dec 22, 2025AnnouncementS&P MidCap 400
S&P MidCap 400: SPX Technologies (SPXC) to join
S&P Dow Jones Indices announced on Dec 22, 2025 that SPX Technologies will join the S&P MidCap 400, replacing Perrigo. Effective after the close on Dec 22, 2025.
- Dec 22, 2025EffectiveS&P MidCap 400
S&P MidCap 400: SPXC inclusion effective
SPX Technologies entered the S&P MidCap 400 after the close on Dec 22, 2025, forcing every tracking fund to hold it.
- Dec 22, 2025AnnouncementS&P MidCap 400
S&P MidCap 400: Pinterest (PINS) to join
S&P Dow Jones Indices announced on Dec 22, 2025 that Pinterest will join the S&P MidCap 400, replacing Under Armour. Effective after the close on Dec 22, 2025.
- Dec 22, 2025EffectiveS&P MidCap 400
S&P MidCap 400: PINS inclusion effective
Pinterest entered the S&P MidCap 400 after the close on Dec 22, 2025, forcing every tracking fund to hold it.
- Dec 22, 2025AnnouncementS&P MidCap 400
S&P MidCap 400: BorgWarner (BWA) to join
S&P Dow Jones Indices announced on Dec 22, 2025 that BorgWarner will join the S&P MidCap 400, replacing Marriott Vacations Worldwide. Effective after the close on Dec 22, 2025.
- Dec 22, 2025EffectiveS&P MidCap 400
S&P MidCap 400: BWA inclusion effective
BorgWarner entered the S&P MidCap 400 after the close on Dec 22, 2025, forcing every tracking fund to hold it.
- Dec 17, 2025AnnouncementS&P MidCap 400
S&P MidCap 400: Corebridge Financial (CRBG) to join
S&P Dow Jones Indices announced on Dec 17, 2025 that Corebridge Financial will join the S&P MidCap 400, replacing Allete, Inc.. Effective after the close on Dec 17, 2025.
- Dec 17, 2025EffectiveS&P MidCap 400
S&P MidCap 400: CRBG inclusion effective
Corebridge Financial entered the S&P MidCap 400 after the close on Dec 17, 2025, forcing every tracking fund to hold it.
- Nov 13, 2025AnnouncementS&P MidCap 400
S&P MidCap 400: Sterling Infrastructure (STRL) to join
S&P Dow Jones Indices announced on Nov 13, 2025 that Sterling Infrastructure will join the S&P MidCap 400, replacing Light & Wonder. Effective after the close on Nov 13, 2025.
- Nov 13, 2025EffectiveS&P MidCap 400
S&P MidCap 400: STRL inclusion effective
Sterling Infrastructure entered the S&P MidCap 400 after the close on Nov 13, 2025, forcing every tracking fund to hold it.
- Oct 6, 2025AnnouncementS&P MidCap 400
S&P MidCap 400: Bentley Systems (BSY) to join
S&P Dow Jones Indices announced on Oct 6, 2025 that Bentley Systems will join the S&P MidCap 400, replacing Western Union. Effective after the close on Oct 6, 2025.
- Oct 6, 2025EffectiveS&P MidCap 400
S&P MidCap 400: BSY inclusion effective
Bentley Systems entered the S&P MidCap 400 after the close on Oct 6, 2025, forcing every tracking fund to hold it.
- Sep 22, 2025AnnouncementS&P MidCap 400
S&P MidCap 400: MP Materials (MP) to join
S&P Dow Jones Indices announced on Sep 22, 2025 that MP Materials will join the S&P MidCap 400, replacing Acadia Healthcare. Effective after the close on Sep 22, 2025.
- Sep 22, 2025EffectiveS&P MidCap 400
S&P MidCap 400: MP inclusion effective
MP Materials entered the S&P MidCap 400 after the close on Sep 22, 2025, forcing every tracking fund to hold it.
- Sep 22, 2025AnnouncementS&P MidCap 400
S&P MidCap 400: TransUnion (TRU) to join
S&P Dow Jones Indices announced on Sep 22, 2025 that TransUnion will join the S&P MidCap 400, replacing Wendy's. Effective after the close on Sep 22, 2025.
- Sep 22, 2025EffectiveS&P MidCap 400
S&P MidCap 400: TRU inclusion effective
TransUnion entered the S&P MidCap 400 after the close on Sep 22, 2025, forcing every tracking fund to hold it.
Announcement and effective dates come from the index providers listed above; press items link to their publisher. Always confirm against the original release before trading — nothing here is investment advice.