Tesla finance chief Zachary Kirkhorn has stepped down, surprising analysts who considered the company veteran of 13 years as a possible successor to CEO Elon Musk, Reuters reported.

The world's largest electric vehicle automaker did not give a reason for the departure. Vaibhav Taneja, 45, replaced Kirkhorn as of Friday and will also retain his role as head of accounting. Kirkhorn plans to stay on at Tesla until the end of the year to support "a seamless transition," it said.

Kirkhorn was seen as an effective and soft-spoken balance to the more volatile Musk, and he was one of the most visible executives who often spoke on calls with analysts and made presentations on strategy and products.