Alleghany Corporation provides property and casualty reinsurance and insurance products in the United States and internationally.

The company operates in three segments: Reinsurance, Insurance, and Alleghany Capital.

The Reinsurance segment offers fire, allied lines, auto physical damage, and homeowners multiple peril reinsurance products; and casualty and other reinsurance products, such as medical malpractice, ocean marine and aviation, accident and health, mortgage, surety, and credit reinsurance products, as well as directors' and officers', errors and omissions, general, and auto liability reinsurance.

This segment distributes its products and services through brokers, as well as directly to insurance and reinsurance companies.

The Insurance segment underwrites specialty insurance coverages in the property, umbrella/excess, general, directors' and officers', and professional liability lines; surety products comprising commercial and contract surety bonds; and workers' compensation insurance products.

This segment distributes its products through independent wholesale insurance brokers, and retail and general insurance agents.

The Alleghany Capital segment provides precision automated machine tool solutions; manufactures custom trailers and truck bodies for the moving and storage industry, and other markets; design, engineering, procurement, construction management, and validation services for pharmaceutical and biotechnology industries; products and services for the funeral and cemetery industries, and precast concrete markets; and hotel management and development services, as well as operates as a toy and musical instrument company, and structural steel fabricator and erector.

The company also owns and manages improved and unimproved commercial land, and residential lots.

As of December 31, 2021, it owned approximately 77 acres of property.

The company was founded in 1929 and is based in New York, New York.