The Ceylon Mercantile Union (CMU) is one of the largest trade unions in the commercial sector in Sri Lanka. A union (labor union in American English; trade union, sometimes trades union, in British English; either labour union or trade union in Canadian English) is a legal entity consisting of employees or workers having a common interest, such as all the assembly workers for one employer, or all the workers...

The Ceylon Mercantile, Industrial and General Workers Union was originally built in 1928 as a white-collar union in the mercantile sector.

After Bala Tampoe became its general secretary in February 1948, it came under the influence of the Lanka Sama Samaja Party. Bala Tampoe (1922 ? - ) is general secretary of the Ceylon Mercantile, Industrial and General Workers Union (CMU) in Sri Lanka. ... The Lanka Sama Samaja Party (Sri Lanka Equal Society Party - LSSP) is a trotskyist political party in Sri Lanka. ...