Sauber are to follow Ferrari and champions Red Bull out of the Formula One teams' association FOTA in a broadening rupture over cost-cutting measures in the sport.
"Last week the Sauber F1 Team has declared its departure from the Formula One Teams' Association FOTA. We have explained the reasons for the decision to FOTA," the Swiss-based team said.
Glamour team Ferrari, who provide Sauber with engines, and Red Bull announced last week that they had given notice of withdrawal. Struggling HRT quit back in January.
The exodus will leave FOTA, created to represent a united front in negotiations with commercial supremo Bernie Ecclestone and governing FIA, with just eight of 12 teams as members and maybe only seven.
Toro Rosso, who also have Ferrari engines and are owned by energy drink company Red Bull, did not attend a FOTA meeting in London last week and had no comment on their status within the organisation.