Analysis
NAICS 4251 is the 2022 industry group for wholesale trade agents and brokers, part of 425 (Wholesale Trade Agents and Brokers).
It has only one more detailed code, 425120, which covers exactly the same activities; the definition, index entries and statistics are on that page.
County Business Patterns counts 34,962 US establishments in this code in 2023, employing 243,788 people at an average annual payroll of $71,985 per employee (55th percentile of national industries). 78% of the establishments have fewer than five employees, which marks it as a small-business industry.
Between 2018 and 2023 the number of establishments fell 10% and employment fell 14%. The 2018 count used NAICS 2017, so part of a large move can come from codes being redefined rather than from businesses opening or closing.