The name comes from the three co-founders. The H is for Hoglund (Greg). The B is for Bracken (Shawn). The Gary is for Jon Gary who left the company shortly after it was founded.
How much you want to bet that the H. B. and G. of this company had ties/tenure in DoD or other governmental departments and were thus situated to reply to RFPs from their previous colleagues.
This is very common in the MIC.