When did AJG join the S&P 500?

Arthur J. Gallagher & Co. joined the S&P 500 index on 2016-05-31.

What sector is AJG in?

AJG is in the Financials sector, Insurance Brokers industry.

AJG — Arthur J. Gallagher & Co.

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

Insurance Brokers · Financials

S&P 500 Timeline

2016-05-31Joined S&P 500

Arthur J. Gallagher & Co. was founded in 1927. The company was reincorporated in Delaware in 1972. The company provides insurance brokerage, reinsurance brokerage, consulting, and third-party property and casualty claims settlement and management services to entities and individuals worldwide. The company's brokerage segment offers brokerage and consulting services to all types of entities—including commercial, nonprofit, public sector entities, insurance companies and insurance capital providers, and to a lesser extent, individuals—in insurance and reinsurance placement, loss risk management, and employer-sponsored benefits plan administration.

Key Facts

Status	Active
Sector	Financials
Industry	Insurance Brokers
Joined	2016-05-31
Tenure	10 yrs

Industry Peers

AON BRO ERIE MRSH WTW

Sector Peers

ACGL AFL AIG AIZ ALL AMP AON APO ARES AXP

Institutional Holdings (13F)

1 institutions hold AJG, totaling 2.4M shares ($514M) · As of 2026Q1

Rank	Institution	Shares	Value
1	GTCR LLC	2.4M	$514M

View all holders →

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