There are 47 firms that generated at least $100 million in IT staffing revenue in 2017, according to a new report by Staffing Industry Analysts that lists the largest IT staffing providers in the US.

IT staffing had estimated revenue of $29.9 billion last year, according to SIA's most recent forecast. It ranks as the second-largest staffing segment in terms of revenue after industrial staffing. The largest staffing firms on this list represented 64% of the market.

The five largest IT staffing firms in the report are:

1. TEKsystems (Allegis Group)
2. ASGN
3. Insight Global
4. Randstad Technologies
5. Kforce

In addition, the report notes that seven firms appearing on this list, which is based on 2017 revenue, did not appear on the year-ago previous list: ALKU, BG Staffing, Compunnel Software Group, Mindlance, Rose International, System One and VACO.

The full list is available to corporate members of SIA.