Around 14,000 delegates reportedly contributed more than £18m over the four-day conference, which ran from 3-6 October.
The ICC also hosted some 2,000 members of the international press, whose activity generated media coverage, said to be worth an additional £29m.
ICC general manager Geoff Fenlon said: "These results are absolutely staggering and I know that I speak for the whole team at the ICC when I say how exceptionally pleased we are to have contributed to this success."
The figure includes over 400 smaller, individual fringe meetings, ranging in size from a dinner for 30 up to a meeting for 600 across the four days of the conference.
Ian Taylor, commercial director at Marketing Birmingham, which manages the Birmingham Convention Bureau, said: "The fact that this is their first conference since being in government no doubt boosted the delegate numbers and media profile considerably but the city simply stepped up to the plate, worked together in partnership, and delivered the conference without a hitch."
The ICC is booked to host the Conservative Party’s Conference in 2012.