What an ICP describes
An ICP describes companies, not people. It usually covers industry, size, location, the technology they use, how their team is set up and the trigger events that make them likely to buy, such as hiring growth or a new regulation. Good ICPs also include the problems those companies have that your product solves, and the signs that a company is a poor fit. The buyer persona then describes the individual people inside those companies.
Example
A company selling route-planning software might define its ICP as: regional delivery companies with 50 to 500 vehicles, operating in more than one city, still planning routes in spreadsheets, and recently hiring dispatchers.
Why it matters
Reps have limited hours. An ICP tells them which accounts deserve those hours and which to skip, so prospecting lists, ad targeting and territory plans all point at the same kind of customer. It improves conversations too, because a rep who knows why a company fits can open with a relevant reason for calling. Teams that skip this step often fill the pipeline with deals that are slow to close, need heavy discounts or cancel soon after signing.
How to use it on calls
Turn your ICP into two or three qualifying questions you can ask early, so you find out quickly whether an account matches. Practice opening calls with the specific reason a company fits, such as a recent expansion, rather than a generic pitch. In interviews, be ready to explain an ICP in plain terms and describe how you would use it to build a prospecting list for the role.