Charles River Laboratories International, Inc. (CRL)

Before a drug reaches humans it is tested for safety, and the regulator requires specific procedures. The company supplies the research animals, the laboratories and the specialists — a stage a developer finds cheaper to outsource than to maintain.

Demand depends on how many programmes the industry is starting, and that in turn on the availability of money at biotech start-ups and on large pharmaceutical budgets. A separate factor is regulators gradually accepting alternative methods in place of animal testing. Risks: shrinking research budgets and ethical pressure. The company pays no dividend.