Index change event
S&P MidCap 400 Additions & Index Changes: TWLO – 14th August 2025
On 14 August 2025, S&P Dow Jones Indices announced 2 index changes affecting 2 companies in the S&P MidCap 400. Twilio replaced Amedisys in the S&P MidCap 400.
Announced
2025-08-14
Effective
August 18, 2025 at 5:00:00 PM
Indexes Affected
S&P MidCap 400
2
Index Changes in Total
1
Additions
1
Deletions
0
Companies that changed index
What happened to the prices
By the next day's close, Twilio, the only addition with price data, had peaked at +6.59%; the deletion, Amedisys, has no next-day prices. The moves are measured from the first extended-hours price after the 17:15 ET announcement.
Only Twilio has next-day prices, so there is no group to compare it with: it opened the next day at +3.82% from the first price after the announcement.
In Short
2 index changes: 1 addition and 1 deletion.
No company moved from one S&P index to another in this announcement.
Largest peak move: Twilio, +6.59% 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: Twilio (TWLO)
1 company joined the S&P MidCap 400 and 1 left, effective 19 August 2025. Twilio is new to the S&P family and Amedisys left the S&P family. Twilio peaked at +6.59% by the next day's close.
Company | Ticker | Source Index | Final Index | Effective Date |
|---|---|---|---|---|
Twilio | TWLO | S&P MidCap 400 | 08/19/2025 |
Company | Ticker | Source Index | Final Index | Effective Date |
|---|---|---|---|---|
Company | Ticker | Source Index | Final Index | Effective Date |
|---|---|---|---|---|
Price reaction
The close price is the last price before the announcement. All percentages are measured from the open price after the announcement.
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 |
|---|---|---|---|---|---|---|---|---|---|---|
Twilio | TWLO | S&P MidCap 400 | 100.84 | 100.80 | +5.16% | +3.97% | +5.06% | +3.82% | +6.59% |
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 |
|---|---|---|---|---|---|---|---|---|---|---|
Not a Investment Advice
This page is research about past price behaviour. It is not a recommendation to buy or sell.