NM négociant-manipulant, one of the big houses/maisons/négociants
RM récoltant-manipulant, a grower who makes his or her own wine
CM coopérative de manipulation, one of the co-operatives
RC récoltant-coopérateur, grower selling wine made by a co-op
MA marque d'acheteur, buyer's own brand, usually a made-up label
So to find a grower's champagne, look out for the letters RM. To find a good grower's champagne (for by no means all of them are worth seeking out), check the name against all those listed in the articles you'll find by clicking on the growers champagne tag below.
