US Department of Labor

“ Establishments primarily engaged in selling merchandise to construction contractors, institutions, industrial users, or businesses are included in Wholesale Trade with a few exceptions. These exceptions are made necessary because of sales to both the general public for personal or household consumption and to businesses, industrial users, or construction contractors. ”

“ In addition to selling, functions frequently performed by wholesale establishments include maintaining inventories of goods; extending credit; physically assembling, sorting, and grading goods in large lots ”