Go / gone south

To go south appears to be of American origin and means to deteriorate or decline as in sales, stock markets, value of assets etc. It seems to have derived from the notion that on a map north is always up at the top and south is down, or when figures or numbers are shown in graph form. When the trend line on a graph turns downwards, it is said to be heading south. When markets fall, financial journalists and reporters often talk of markets heading south. In this sense, it is a relatively modern expression, and first appears in the 1920s. An earlier citation for the expression dates from the mid-19th century and appears in the Webster New International Dictionary, in the sense of absconding with ill-gotten gains. Going south in this context originates from the then common practice of US criminals heading south for the Mexican border. See also Go/gone west.