Despite Takashi Kurita's "Death to Mercenaries" command at the start of the Fourth Succession War in 3028, the Cutthroats initially remained in the Dragon's employ. In May 3029, the Cutthroats successfully invaded the Federated Suns world of Groveld III. Although they took the world, the planetary militia put up a hard fight, and a commando team of survivors from the militia infiltrated the Cutthroats' camp and assassinated their second-in-command.
Freshly promoted executive officer, Matthew Simonson, responding to rising anti-mercenary sentiment in the Combine, deposed Colonel McGee in a bloody power struggle. Now known as Simonson's Cutthroats, the unit left the Combine's service and travelled to Galatea, then considered the "mercenary star" of the Inner Sphere, where they replaced their losses and searched for a new employer. They eventually found one in the newly-formed Federated Commonwealth, working for House Davion. 
- NAIS The Fourth Succession War Military Atlas Volume 2, p. 26, "Federated Suns Front"
- Field Manual: Mercenaries, Revised, p. 100, "Simonson's Cutthroats: Reluctant Renegades"