Marock said that the decision to step down was “very difficult”, and he was “grateful” to have led the firm for the past nine nine years.
He has offered to provide support during the transition period as the board begins its search for a new CEO, led by executive chairman Edward Creasy.
Creasy will remain executive chairman until the search for a permanent Group CEO is completed.
Marock said: “I am particularly proud that together we have made it a great place to work, one that has flourished into a vibrant, client-focused, entrepreneurial, and much enlarged, successful business.
“At the same time, after so many years of intensive focus, I feel a strong need to have time to recharge fully, reflect, and ultimately decide on the next stage of my career.”
Creasy added: “Under his leadership, Charles Taylor has grown substantially on numerous fronts, just as important, we have developed a reputation as being one of the best companies to work for in the global insurance market.
“We are sad to see him go, and wish him all the best in his future endeavours.”
In addition to Marock’s departure and Creasy’s appointment, Tamer Ozmen has rejoined the Charles Taylor board, while Richard Yerbury has been promoted to group COO.