The first half of the 20th century saw a rise in the demand for pima cotton. A group of US family farmers decided that the quality of the cotton must not suffer due to the higher demand. So in 1954 they established the Supima non-profit organization. To goal was to group pure and high quality pima cotton in the US. To better manage and promote Supima cotton, they started a license program. These days the Supima® trademark is quite an exclusive club.
Supima cotton needs a hot arid climate and irrigation to grow. So only a few areas in the US, like the Southwest and Far West, are suitable for cultivation. Of all the cotton grown in America, pima cotton makes up around 3%. The number of licensed Supima manufacturers and retailers is quite small, as we saw above. So Supima cotton is even more rare.