The Black Sun - Exchange War was a struggle for control of the Coruscant Undercity by two of the galaxy's most powerful criminal organizations, the Black Sun and The Exchange. The initial conflict grew over failed negotiations on Vjun seeking to set the bounderies of each criminal faction's control of the spice trade. Much of the responsibility for the breakdown of negotiations is laid at the feet of then Black Sun Overlord Cayce Urriah, who took an instant and intense dislike for Exchange crime boss Hulio Andel.
The Black Sun had previously been content with its large criminal and pirate empire covering a large swath of territory in the galactic south, from Nar Shaddaa all the way to Dagobah. With the return of Cayce Urriah to the Black Sun and her partnership with Klugga the Hutt, Cayce Urriah pushed to expand the Black Sun's activities into the galactic core, sparking an intense conflict with The Exchange.
The war included several assassination attempts on all the key players, as well as spectacular acts of terror in Mos Eisley and in the Coruscant undercity. The crime war ended with the disappearance of Hulio Andel, and the Black Sun's reluctant retreat from major criminal activity on Coruscant. The Black Sun went on to a revival under the leadership of Huttila the Hutt, while The Exchange faded into the background.