Swiss-based Sauber have parted company with team principal Monisha Kaltenborn the team confirmed late on Wednesday.
A statement from Sauber's Chairman Pascal Picci said the split would take place with immediate effect.
"Longbow Finance SA regrets to announce that, by mutual consent and due to diverging views of the future of the company, Monisha Kaltenborn will leave her positions with the Sauber Group effective immediately," Picci's statement read.
"We thank her for many years of strong leadership, great passion for the Sauber F1 Team and wish her the very best for the future. Her successor will be announced shortly."
The split comes amid speculation Kaltenborn wanted equal treatment for the team’s drivers after the team owner’s allegedly wanted preferential treatment for Marcus Ericsson.
Sauber statement denies reports that "drivers have not been, and are not being, treated equally". But oddly makes no mention of Kaltenborn
— Andrew Benson (@andrewbensonf1) June 21, 2017
The team refuted those rumours in a separate statement.
"The owners and board of Sauber Motorsport AG take strong exception to speculative and widespread media reports today that our race drivers have not been, and are not being, treated equally," said Picci.
"This is not only patently untrue, it would be contrary to the team's absolute and longstanding commitment to fair competition.
"These reports, attributed to anonymous 'sources', are highly detrimental to both Marcus Ericsson and Pascal Wehrlein as well as to the management and all staff of the Sauber F1 Team."
— Jeff Pappone (@jpappone) June 22, 2017
Kaltenborn had been with Sauber since 2010, and was a part owner after buying shares in 2011. In 2012, she became F1’s first female principal.
Former Midland, Hispania and Caterham F1 boss Colin Kolles is rumoured to be among those being considered to replace her.