will assume her new role on 1 April.
"Lois's talent in creating brand experiences for large corporations and governments, together with her experience in managing and growing a global network, is unparalleled," said Fitch founder and chairman Rodney Fitch.
"Her skills have resulted in exceptional business growth, which will be a significant asset both to Fitch and our valued clients. I look forward to working with her."
Jacobs was international president of Jack Morton Worldwide for eight years.