Wholesalers have more influence on their purchases than commonly thought.
PM magazine's “National Profile of Purchasing Trends in the Plumbing Industry” study completed late last year found that only 4% of plumbing and mechanical contractors typically purchased from a single wholesaler in a month's time. That's about the same as the 3% who answered the same way to a similar study performed by PM in 1992. But from there the results diverge significantly.