An ICP is a data-driven description of the company type most likely to buy, retain, and expand — defined by industry, headcount, tech stack, geography, and buying behavior. Not to be confused with a buyer persona (which describes a person), an ICP describes the account.
A precise ICP sharpens every growth lever: which channels to invest in, what to say in SDR outreach, which deals to qualify in or out, and where to focus product roadmap investment. Most early-stage SaaS companies under-invest in ICP definition and end up serving segments with incompatible needs — high CAC, high churn, and low expansion as a result.