The new outfit, called Superhero, was created after NMI's account director, Dominic Stevenson, and creative directors, Nathan Church and Alex Hinge, bought out the company's advertising concern.
In recent years, NMI had branched out into areas such as production, media and security cameras. Stevenson, Church and Hinge decided to go into business in an effort to refocus on advertising.
They will be backed by Alan Page (formerly of Yellowhammer) and Toby Constantine, a former marketing director of Times Newspapers and Metro International.
Superhero will launch with offices in Clerkenwell and a team of eight producers, creatives and account handlers.