The Monmouthshire and South Wales Coal Owners' Association (MSWCOA) was an association of mine owners in South Wales that was active between 1873 and 1955.It fought wage increases, safety regulations, unionisation and other changes that would cut into profits. It managed to link miners wages, which were based on piece-work, to the price of coal.It was involved in various labour disputes, including a lengthy strike in 1926. The coal mines became unprofitable in the 1930s and were nationalized in 1947, making the association irrelevant.