Stocks joining the indexes next
Funds must own every addition by the effective close; this register tracks the window. Data as of Sep 15, 2026.
14days
until RBLX (Roblox) joins at the close
Effective 04 SEPT 2026
Pending entries
1 announced, not yet effective
| No. | Stock | Index | Days left | Since announced | Date effective | Date announced | Replaces |
|---|---|---|---|---|---|---|---|
| 043 | RBLXRobloxAnnounced but not yet effective as of the dataset date. | Nasdaq-100 | 14 | — | 04 SEPT 2026 | 14 AUG 2026 | Paccar |
Entered in the last 90 days
Returns measured from the effective-date close
| No. | Stock | Index | Run-up 30d | 1W | 1M | 3M | 6M | 1Y | Date effective |
|---|---|---|---|---|---|---|---|---|---|
| 042 | SNOWSnowflake | Nasdaq-100 | +10.2% | +1.5% | +6.7% | Not yet elapsed | Not yet elapsed | Not yet elapsed | Jun 22, 2026 |
Losses are entered in red. A blank cell means that window hasn't elapsed yet.
What usually happens after the bell
Across 43 tracked additions
| Window after close | Average | Median | Finished higher | vs index |
|---|---|---|---|---|
| 1W | -0.9% | -1.4% | 38% | -1.1% |
| 1M | -0.4% | +1.9% | 52% | -1.3% |
| 3M | +4.6% | +5.6% | 56% | +0.9% |
| 6M | +13.1% | +13.4% | 68% | +5.0% |
| 1Y | +21.0% | +10.2% | 61% | +3.6% |
| Run-up, 30 days before the close | +20.0% | Average move into past inclusions | ||
How index additions work
Index committees review the indexes we track on a published schedule and also make ad hoc changes when a constituent is acquired, delisted or no longer eligible. A change is announced first and only takes effect after the close on the effective date. Between those two dates, every fund tracking the index has to buy the incoming stock, which is why the window matters to traders.
Of the 43 additions with a recorded announcement date, the median notice between the announcement and the effective close is 10 days.
What happens to a stock after it joins an index
Inclusion is often described as a guaranteed pop. The tracked history is more mixed: the average stock ran up +20.0% in the 30 days into the effective close, then returned -0.9% in the first week (38% of additions were positive), -0.4% after one month, and +21.0% after a year. Returns are measured from the effective close and can also be viewed against the index itself, so a rising market doesn't get counted as an inclusion effect.
Best one-year outcome in this set: PLTR (Palantir Technologies) at +302.8%. Worst: TTD (The Trade Desk) at -61.7%.
When are index changes announced?
Review cadences differ by index provider. Scheduled review, announcement and effective dates for the next twelve months are listed on the index review calendar. Ad hoc changes — a takeover, a bankruptcy, a fast-track promotion — are announced outside that schedule, usually with a few days' notice.
Currently pending: RBLX (Nasdaq-100, effective Sep 4, 2026).
Open the index review calendar — pending now: RBLX.
Most recent additions
- SNOW — Snowflake joined the Nasdaq-100 on Jun 22, 2026, replacing Zscaler.
- CRWV — CoreWeave joined the Nasdaq-100 on Mar 23, 2026, replacing Marvell Technology.
- COIN — Coinbase Global joined the Nasdaq-100 on Dec 22, 2025, replacing ON Semiconductor.
- HOOD — Robinhood Markets joined the Nasdaq-100 on Dec 22, 2025, replacing Biogen.
- APP — AppLovin joined the Nasdaq-100 on Dec 22, 2025, replacing GlobalFoundries.