Index change event
S&P 500 & SmallCap 600 Additions & Index Changes: ARES, SEZL & VITL – 8th December 2025
On 8 December 2025, S&P Dow Jones Indices announced 6 index changes affecting 6 companies in the S&P 500 and S&P SmallCap 600. The most notable move was Ares Management joining the S&P 500.
Announced
2025-12-08
Effective
December 10, 2025 at 4:00:00 PM
Indexes Affected
S&P 500, S&P SmallCap 600
6
Index Changes in Total
3
Additions
3
Deletions
0
Companies that changed index
What happened to the prices
By the next day's close, the 3 additions with price data had peaked at an average of +8.85%, against +0.28% for the 3 deletions. The largest mover was Ares Management, with a peak of +10.58%. The moves are measured from the first extended-hours price after the announcement, except for 1 name with no recorded trade after 17:15 ET, measured from the 16:00 ET close.
Heidrick & Struggles Intl went against the other deletions: its next-day open was +0.07% from the post-announcement price, while the 3 deletions averaged -0.21%.
In Short
6 index changes: 3 additions and 3 deletions.
No company moved between indexes, and the changes took effect on 2 dates.
Largest peak move: Ares Management, +10.58% by the next day's close.
The changes, index by index
An empty cell means the company was not in the S&P family before, or left it.
S&P 500 Additions: Ares Management (ARES)
1 company joined the S&P 500 and 1 left, effective 11 December 2025. Ares Management is new to the S&P family and Kellanova left the S&P family. Ares Management peaked at +10.58% by the next day's close.
Company | Ticker | Source Index | Final Index | Effective Date |
|---|---|---|---|---|
Ares Management | ARES | S&P 500 | 12/11/2025 |
Company | Ticker | Source Index | Final Index | Effective Date |
|---|---|---|---|---|
S&P SmallCap 600 Additions: Sezzle (SEZL) and Vital Farms (VITL)
2 companies joined the S&P SmallCap 600 and 2 left, effective 11 and 15 December 2025. Sezzle and Vital Farms are new to the S&P family and Heidrick & Struggles Intl and Vital Energy left the S&P family. The 2 additions with price data peaked at an average of +7.99% by the next day's close, led by Sezzle at +8.63%.
Company | Ticker | Source Index | Final Index | Effective Date |
|---|---|---|---|---|
Sezzle | SEZL | S&P SmallCap 600 | 12/15/2025 | |
Vital Farms | VITL | S&P SmallCap 600 | 12/11/2025 |
Company | Ticker | Source Index | Final Index | Effective Date |
|---|---|---|---|---|
Price reaction
The close price is the last price before the announcement. Percentages are measured from the open price after the announcement, or from the close for a company with no price after it.
S&P 500 Additions Changes
Company | Ticker | Source Index | Final Index | Close Price | Open Price at Announcement | % Change +5 min | % Change +30 min | % Change at 20:00 Hrs | % Change by Next Day Open | % Highest Change by Next Day Close |
|---|---|---|---|---|---|---|---|---|---|---|
Ares Management | ARES | S&P 500 | 164.26 | 167.31 | +6.39% | +5.13% | +5.42% | +6.87% | +10.58% |
S&P MidCap 400 Additions Changes
Company | Ticker | Source Index | Final Index | Close Price | Open Price at Announcement | % Change +5 min | % Change +30 min | % Change at 20:00 Hrs | % Change by Next Day Open | % Highest Change by Next Day Close |
|---|---|---|---|---|---|---|---|---|---|---|
S&P SmallCap 600 Additions Changes
Not a Investment Advice
Company | Ticker | Source Index | Final Index | Close Price | Open Price at Announcement | % Change +5 min | % Change +30 min | % Change at 20:00 Hrs | % Change by Next Day Open | % Highest Change by Next Day Close |
|---|---|---|---|---|---|---|---|---|---|---|
Sezzle | SEZL | S&P SmallCap 600 | 67.70 | 68.93 | +5.25% | +5.18% | +4.74% | +4.12% | +8.63% | |
Vital Farms | VITL | S&P SmallCap 600 | 31.73 | 32.50 | +3.23% | +4.06% | +2.25% | +1.11% | +7.35% |
Not a Investment Advice
This page is research about past price behaviour. It is not a recommendation to buy or sell.