Index change event
S&P MidCap 400 & SmallCap 600 Additions & Index Changes: ELAN & SRPT – 26th August 2025
On 26 August 2025, S&P Dow Jones Indices announced 4 index changes affecting 3 companies in the S&P MidCap 400 and S&P SmallCap 600. The most notable move was Elanco Animal Health joining the S&P MidCap 400.
Announced
2025-08-26
Effective
September 1, 2025 at 5:00:00 PM
Indexes Affected
S&P MidCap 400, S&P SmallCap 600
4
Index Changes in Total
2
Additions
2
Deletions
1
Companies that changed index
What happened to the prices
By the next day's close, Elanco Animal Health, the only addition with price data, had peaked at +6.67%, against +0.98% for the 2 deletions. The largest mover was Elanco Animal Health, with a peak of +6.67%. 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.
No name moved against its group: every deletion with price data opened the next day below the post-announcement price. The single addition, Elanco Animal Health, opened at +4.50%.
In Short
4 index changes: 2 additions and 2 deletions.
1 company moved from one S&P index to another, out of 3 in total.
Largest peak move: Elanco Animal Health, +6.67% 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.
Company | Ticker | Source Index | Final Index | Effective Date |
|---|---|---|---|---|
S&P MidCap 400 Additions: Elanco Animal Health (ELAN)
1 company joined the S&P MidCap 400 and 1 left, effective 2 September 2025. Elanco Animal Health is new to the S&P family and Sarepta Therapeutics moved down to the S&P SmallCap 600. Elanco Animal Health peaked at +6.67% by the next day's close.
Company | Ticker | Source Index | Final Index | Effective Date |
|---|---|---|---|---|
Elanco Animal Health | ELAN | S&P MidCap 400 | 09/02/2025 |
S&P SmallCap 600 Additions: Sarepta Therapeutics (SRPT)
1 company joined the S&P SmallCap 600 and 1 left, effective 2 September 2025. Sarepta Therapeutics moved down from the S&P MidCap 400 and Brookline Bancorp left the S&P family. Sarepta Therapeutics peaked at +1.59% by the next day's close.
Company | Ticker | Source Index | Final Index | Effective Date |
|---|---|---|---|---|
Sarepta Therapeutics | SRPT | S&P MidCap 400 | S&P SmallCap 600 | 09/02/2025 |
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 |
|---|---|---|---|---|---|---|---|---|---|---|
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 |
|---|---|---|---|---|---|---|---|---|---|---|
Elanco Animal Health | ELAN | S&P MidCap 400 | 17.90 | 17.99 | +3.45% | +4.72% | +3.39% | +4.50% | +6.67% |
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 |
|---|---|---|---|---|---|---|---|---|---|---|
Sarepta Therapeutics | SRPT | S&P MidCap 400 | S&P SmallCap 600 | 18.26 | 18.29 | +0.71% | +0.93% | +0.11% | -0.16% | +1.59% |
Not a Investment Advice
This page is research about past price behaviour. It is not a recommendation to buy or sell.