Sorry, I should have been more clear. The acronym is MBB (McKinsey, Bain, and BCG) that I'm familiar with when referring to the top consulting companies. MBBD (McKinsey, Bain, BCG, and Deloitte) is a reddit joke that I've seen a bunch. The original commenter was using McKinsey, Bain, BCG, and Accenture to refer to the "big 4" consulting firms. I've worked with Accenture before, but I've never heard anyone group Accenture with those other consulting firms.