Tesla’s Chief Financial Officer Zachary Kirkhorn has stepped down after 13 years at the EV maker.

It is reported he will continue to serve through the end of the year to support the transition.

Chief accounting officer, Vaibhav Taneja is set to succeed him and will handle both roles simultaneously.

In a statement on LinkedIn, Kirkhorn said:

“As I shift my responsibilities to support this transition, I want to thank the talented, passionate, and hard-working employees at Tesla, who have accomplished things many thought not possible. I also want to thank Elon for his leadership and optimism, which has inspired so many people.”

Kirkhorn’s departure has come as a surprise and has raised questions about succession in Tesla’s top ranks.  He was considered a strong contender to succeed Musk as CEO.

Earlier this year, Tesla was accused of ‘mismanagement’, with Musk facing shareholder frustration over his commitment to other companies. In April, 17 ‘long-term’ shareholders – who hold $1.5 billion in Tesla stock – wrote an open letter, which among other details, said that the board “failed to ensure that the CEO is appropriately focused on Tesla”.

On social media, Tesla CEO Elon Musk thanked Kirkhorn for his contributions, and acknowledged his service over thirteen “often difficult” years.

Tesla has been cutting its prices across its vehicle lineup amid the EV price war, which has seen several other automakers – such as startup Lucid –  slashing their prices to get a competitive edge, challenging Musk’s firm.