zanzibar: IMC is that the FIDE title for Intl Master of Composition, or as top hits in Google suggest, is it Intl Master of Correspondence Chess?
FIDE seems to suggest they award both:
See rule 0.3:
<0.32 Titles for chess composition, the judging unit being the Permanent Commission for Chess Compositions: Grandmaster of Solving (GS), International Master of Solving (IMS), FIDE Master of Solving (FMS); Grandmaster of Composing (GMC), International Master of Composing (IMC), FIDE Master of Composing (FMC); International Judge of Chess Composition (IJCC).
<0.33 Titles for correspondence chess, the judging unit being the International Correspondence Chess Federation (ICCF).>
I see the potential for confusion here, compare ICCF title and IJCC. My preference for <CG> would be to err on the side of verbosity for these lesser known titles (spell out the name with abbrev in parens).
(Note, link is to a "stale" handbook, validity expiring on June 30, 2013 - not sure where most recent rules are)
Rule 0.4 answers my earlier question about the validity of CM title:
<0.4 The titles are valid for life from the date confirmed.>