What is index reconstitution?

Index reconstitution is the periodic process by which an index provider re-evaluates which securities qualify for an index and updates its membership and weights. Rules-based indexes like Russell rebuild membership on scheduled dates, while committee-based indexes like the S&P 500 review changes as needed and quarterly.

When is Russell reconstitution?

The Russell US Indexes annual reconstitution is effective after the close on the fourth Friday of June — June 26, 2026. Starting in 2026, FTSE Russell added a second, semi-annual reconstitution effective after the close on the second Friday of December — December 11, 2026 — the first time the Russell US Indexes reconstitute twice in a year. Always verify the current schedule with FTSE Russell.

SAIR stands for the MSCI Semi-Annual Index Review, one of MSCI's two larger reviews each year (in May and November), where rules-based additions, deletions, and free-float and weight changes are applied across the MSCI ACWI, World, and Emerging Markets indexes. MSCI also runs smaller quarterly reviews in February and August. For 2026, the remaining reviews are the August review (effective September 1, 2026) and the November review (effective December 1, 2026).

Why do rebalances move stocks?

Passive funds that track an index must buy and sell to match changes in membership and weights, creating large, predictable, often concentrated trading flows around the effective date. Because trillions of dollars in passive AUM track major indexes, additions can see buying pressure and deletions selling pressure, especially near the close on the effective day.

Index Rebalancing Calendar

Updated June 1, 2026 — forward calendar through December 2026. Dates follow each provider's published rules (e.g., S&P 500 and Nasdaq-100 quarterly effective the third Friday of Mar/Jun/Sep/Dec; Russell annual reconstitution effective the fourth Friday of June). Passive AUM figures are illustrative estimates. Always confirm against the official S&P DJI, FTSE Russell, MSCI, Nasdaq, STOXX, and exchange schedules before acting.

Global Index Coverage

Index	Provider	Selection	Frequency	Passive AUM	Next Inflection	Next Rebalance	Impact Report
S&P 500United States	S&P DJI	Committee	As-needed + Quarterly	$5.3T	Jun 12, 2026Q2 Announcement	Jun 19, 2026Q2 Effective	S&P 500
Russell 1000/2000United States	FTSE Russell	Rules-based	Semi-annual (Jun + Dec, new 2026)	$10.6T	Jun 26, 2026Annual Reconstitution (effective)	Dec 11, 2026Semi-Annual Reconstitution (inaugural)	Russell
MSCI ACWI / World / EMGlobal	MSCI	Rules-based	Quarterly (Feb/May/Aug/Nov)	$16.5T	Aug 12, 2026August Review Announcement	Sep 1, 2026August Review Effective	MSCI
NASDAQ-100United States	Nasdaq	Rules-based	Annual Dec + Quarterly weight	$1.5T	Jun 9, 2026Q2 Announcement	Jun 19, 2026Q2 Effective	NDX
FTSE 100United Kingdom	FTSE Russell	Rules-based	Quarterly	$800B	Jun 4, 2026Q2 Review Snapshot	Jun 19, 2026Q2 Effective	Europe
DAX 40Germany	STOXX	Rules-based	Quarterly	$600B	Jun 3, 2026Q2 Announcement	Jun 23, 2026Q2 Effective	Europe
STOXX Europe 600Europe	STOXX	Rules-based	Quarterly	$1.2T	Jun 1, 2026Q2 Announcement	Jun 22, 2026Q2 Effective	Europe
Nikkei 225Japan	Nikkei Inc.	Committee	Annual October	$1.0T	Sep 2026Annual Announcement	Oct 2026Annual Effective	-
TOPIXJapan	JPX	Rules-based (post-2026)	Annual October	$1.5T	Aug 2026Phase 2 Base Date	Oct 2026Phase 2 Selection	-
Hang SengHong Kong	HSI Co.	Committee + Rules	Quarterly	$400B	May 2026Q2 Announcement	Jun 2026Q2 Effective	-
CSI 300China	CSI	Rules-based	Semi-annual	$800B	May 2026Semi-annual Announcement	Jun 15, 2026Effective	-
KOSPI 200South Korea	KRX	Rules-based	Semi-annual	$500B	May 2026Semi-annual Announcement	Jun 2026Effective	-
S&P/ASX 200Australia	S&P DJI	Rules-based	Quarterly	$300B	Jun 5, 2026Q2 Announcement	Jun 19, 2026Q2 Effective	-

Upcoming Events (June - December 2026)

Jun 12

HIGH

S&P 500 Q2 Rebalance Announcement

Quarterly constituent changes announced (second Friday of the quarter month); effective at the close of Jun 19.

~$5.3T passive AUM tracking (est.)

Jun 19

HIGH

S&P 500, Nasdaq-100 & Global Quarterly Effective

Third-Friday quarterly rebalance: S&P 500, Nasdaq-100, FTSE 100, S&P/ASX 200 and others go effective. Heaviest trading at the close.

~$6.8T combined passive AUM (est.)

Jun 22-23

MEDIUM

STOXX Europe 600 & DAX 40 Effective

European quarterly constituent and weight changes go live.

~$1.8T combined passive AUM (est.)

Jun 26

CRITICAL

Russell Annual Reconstitution Effective

Annual rebuild of the Russell 1000/2000/3000 effective after the close on the fourth Friday of June — historically the largest single-day forced-trading event in U.S. equities.

~$10.6T passive AUM tracking (est.)

Aug 12

MEDIUM

MSCI August Index Review Announcement

Quarterly review adds, deletes and weight changes announced across MSCI ACWI / World / EM; effective Sep 1.

~$16.5T passive AUM tracking (est.)

Sep 1

HIGH

MSCI August Review Effective

New MSCI composition goes live (effective the close of the last business day of August).

~$16.5T passive AUM tracking (est.)

Sep 18

HIGH

S&P 500 & Nasdaq-100 Q3 Effective

Third-Friday quarterly rebalance for the major U.S. indexes.

~$6.8T combined passive AUM (est.)

Nov 11

MEDIUM

MSCI November Index Review Announcement

One of MSCI's two larger semi-annual reviews; changes effective Dec 1.

~$16.5T passive AUM tracking (est.)

Dec 1

HIGH

MSCI November Review Effective

New MSCI composition goes live (effective the close of the last business day of November).

~$16.5T passive AUM tracking (est.)

Dec 11

CRITICAL

Russell Semi-Annual Reconstitution Effective (Inaugural)

First-ever second annual reconstitution of the Russell US Indexes, effective after the close on the second Friday of December — new from 2026. Flows are expected to be smaller than the June reconstitution.

~$10.6T passive AUM tracking (est.)

Dec 18

HIGH

S&P 500 Q4 & Nasdaq-100 Annual Effective

Third-Friday quarterly rebalance plus the Nasdaq-100 annual reconstitution go effective on the same day.

~$6.8T combined passive AUM (est.)

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