When did SO join the S&P 500?

Southern Company joined the S&P 500 index on 1957-03-04.

What sector is SO in?

SO is in the Utilities sector, Electric Utilities industry.

SO — Southern Company

Name: SO Institutional Holdings (13F) — 2026Q1
Creator: SEC EDGAR
License: https://www.sec.gov/data

Electric Utilities · Utilities

Southern Company is a holding company engaged in power generation and sales. It operates through the following segments: Traditional Power Operations, Southern Power, and Southern Company Gas. The Traditional Power Operations segment consists of vertically integrated utilities with generation, transmission, and distribution facilities serving customers in Alabama, Georgia, Florida, and Mississippi. The Southern Power segment builds, acquires, owns, and manages power generation assets, including renewable energy projects, and sells electricity wholesale. The Southern Company Gas segment distributes natural gas through distribution facilities in Illinois, Georgia, Virginia, New Jersey, Florida, Tennessee, and Maryland.

Key Facts

Status	Active
Sector	Utilities
Industry	Electric Utilities
Joined	1957-03-04
Tenure	69 yrs

S&P 500 Timeline

1957-03-04Joined S&P 500

Industry Peers

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Sector Peers

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Institutional Holdings (13F)

2,596 institutions hold SO, totaling 1.94B shares ($102.4B) · As of 2026Q1

Rank	Institution	Shares	Value
1	VANGUARD CAPITAL MANAGEMENT LLC	144.8M	$13.9B
2	BlackRock, Inc.	131.7M	$10.6B
3	Capital World Investors	76.5M	$7.5B
4	STATE STREET CORP	84.7M	$6.7B
5	JPMORGAN CHASE & CO	84.5M	$4.4B
6	MORGAN STANLEY	62.0M	$4.3B
7	GEODE CAPITAL MANAGEMENT, LLC	29.4M	$2.9B
8	BARCLAYS PLC	69.5M	$2.8B
9	VANGUARD PORTFOLIO MANAGEMENT LLC	26.9M	$2.6B
10	FMR LLC	33.0M	$2.3B

View all holders →

Data source: Wikipedia · CC BY-SA 4.0 · SEC EDGAR 13F · Updated 2026-07-10