Allen & Overy managing partner Andrew Ballheimer is set to retire from the Magic Circle firm next year.

He will step down on April 30, 2020, and therefore not run in the upcoming elections for his role, with nominations open for the position of managing partner.

Partners at the firm were informed of his intention to retire on Monday afternoon.

In a statement, Ballheimer said: "This has been an immensely difficult decision for me, as A&O has been my professional home for almost a lifetime and it has been a unique privilege to serve in my current role. I am happy that the firm is in such great financial shape and, as a result, after 35 years in private practice including 15 years in various senior leadership roles at A&O, I feel it is a good time to explore new challenges in the outside world, including in the wider community, before I am too old!"

He has spent three years as managing partner at the firm, after being elected alongside senior partner Wim Dejonghe in 2016.

Dejonghe's role is also up for renewal, with nominations also open.

The nomination period will close on December 12 and voting for the positions will run through February. The successful candidates for both positions will be announced in the final week of February, according to one person familiar with the process.

Ballheimer started his career as an associate at A&O in 1987, making partner in 1994 in the corporate practice and working in both the Tokyo and New York offices of A&O before returning to London in 2003.

In 2010, he was appointed co-head of the global corporate practice and has extensive experience in corporate finance, specialising in complex cross-border M&A and equity capital markets work.

Along with Dejonghe, he played a crucial role in steering the firm through its recent merger discussions with U.S. firm O'Melveny & Myers, which collapsed in September.

He also oversaw strong financial growth at the firm in recent years, which most recently grew its top line by 5% to hit £1.627 billion ($2 billion) for the 2018-19 financial year.