Charles River Laboratories is the largest outsourced contract research organization (CRO) for preclinical drug development. Charles River provides the tools, models, and services that pharmaceutical and biotech companies need to test drug safety before human clinical trials — a regulatory requirement enforced by the FDA and other global regulators. Charles River operates three segments: Discovery and Safety Assessment (DSA, ~60% of revenue), Research Models and Services (RMS, ~21%), and Manufacturing Solutions (~19%). DSA is the core business, conducting toxicology and safety studies in animals and in vitro systems required before a drug enters human trials, as well as earlier-stage discovery services. RMS produces and sells purpose-bred rodents and non-human primates (NHPs) used in drug research, and also manages vivarium operations inside client facilities. Manufacturing Solutions provides microbial contamination testing and biologics testing to support pharmaceutical manufacturing quality control, as well as contract development and manufacturing for cell and gene therapies. Charles River charges fees on a per-study or per-project basis, with revenue driven by study volume, study mix, and pricing. Its cost structure is largely fixed, so margins are sensitive to utilization. A key strategic initiative involves internalizing NHP supply through recent acquisitions to reduce input costs. Charles River also plans to divest roughly 7% of revenue in non-core businesses, and is investing in New Approach Methodologies to stay relevant as regulators gradually shift away from certain animal studies.