From English Wikipedia
Ultra Software Corporation was a spinoff company created in 1988 as a subsidiary of Konami of America, in an effort to get around Nintendo of America's strict licensing rules for the North American Konami release games for Nintendo consoles. One of these rules was that a third-party company could only publish up to five games per year for the Nintendo Entertainment System in the US. This was hardly convenient for Konami, which had begun releasing more than ten games a year for both the Family Computer and Family Computer Disk System in Japan. With a greater library than they were allowed to localize, Konami formed the Ultra Games brand to extend their annual library to ten games a year.
Ultra's first game was the NES version of Metal Gear. At first, Ultra was dedicated to localizing Konami's pre-existing software from Japan, but later they began publishing works from other companies as well. Some of Konami's most notable games released under the Ultra label include Operation C (an original Game Boy installment of the Contra series), Snake's Revenge (a sequel to the original Metal Gear) and the first few Teenage Mutant Ninja Turtles games for the NES and Game Boy.
After the North American launch of the Super Nintendo Entertainment System, Nintendo became less strict on the number of games third-parties could publish. As a result, Ultra Games began losing its purpose and Konami shortly dropped the label in 1992.
In Europe, Konami established the Palcom Software Limited subsidiary for similar purposes. Their library was similar to Ultra's, but the company also published games that were not released in America, notably Parodius and Pop'n Twinbee.