Tenable Holdings Set to Join S&P SmallCap 600
Rhea-AI Summary
Tenable Holdings (NASD: TENB) will be added to the S&P SmallCap 600, replacing Leggett & Platt (NYSE: LEG), effective prior to the open on August 31, 2026, according to S&P Dow Jones Indices. Leggett & Platt is being acquired by Somnigroup International (NYSE: SGI), a constituent of the S&P MidCap 400, in a transaction expected to close soon, subject to final conditions.
The index change will place Tenable in the Information Technology sector within the S&P SmallCap 600, while Leggett & Platt, classified in Consumer Discretionary, will be deleted from that index on the same effective date.
Positive
- Tenable added to S&P SmallCap 600 effective August 31, 2026
- Somnigroup acquiring Leggett & Platt, triggering index rebalancing
Negative
- Leggett & Platt removed from S&P SmallCap 600 on August 31, 2026
Key Figures
Historical Context
| Date | Event | Sentiment | 24h Move | Catalyst |
|---|---|---|---|---|
| Aug 26 | Management appointment | Neutral | -1.9% | New president appointed to oversee Leggett & Platt operations |
| Aug 26 | Acquisition completion | Positive | -1.9% | All-stock combination with Leggett & Platt completed |
| Aug 20 | Merger approval | Positive | -2.7% | Leggett & Platt shareholders approved the proposed Somnigroup merger |
| Aug 06 | 2Q26 earnings | Positive | -6.8% | Profitability improved and full-year adjusted EPS guidance was provided |
| Aug 06 | Dividend declaration | Positive | -6.8% | Third-quarter cash dividend declared at $0.17 per share |
24h Move is the share-price change in the day after each event; other market factors may also have contributed.
SGI's five selected prior events all had negative 24-hour reactions despite neutral or positive event descriptions.
AI-generated analysis. How Rhea-AI works. Not financial advice.
Following is a summary of the changes that will take place prior to the open of trading on the effective date:
Effective Date | Index Name | Action | Company Name | Ticker | GICS Sector | |
Aug 31, 2026 | S&P SmallCap 600 | Addition | Tenable Holdings | TENB | Information Technology | |
Aug 31, 2026 | S&P SmallCap 600 | Deletion | Leggett & Platt | LEG | Consumer Discretionary | |
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SOURCE S&P Dow Jones Indices