Entertainment Software Publishing (more commonly ESP) is a Japanese videogame publisher formed by a group of developers in 1996, initially focused on releasing games for the Saturn. Many of the founding companies were small, and worried they would not have the resources to create, publish, and market, games in the 32-bit era. Unusually ESP were willing to make small print runs of games (10,000), which Treasure in particular made use of.
According to Wikipedia