Chief Justice of Nigeria (CJN) Justice Tanko Muhammad resigned from his position on health grounds, his media aide Isah Ahuraka said on Monday.
President Muhammadu Buhari swore in Tanko as CJN in January 2019 following the suspension and sack of former CJN Walter Onnoghen.
Justice Olukayode Ariwoola is the next most senior after Justice Mary Odili retired on May 12 after attaining the retirement age of 70.
Ahuraka confirmed to the News Agency of Nigeria that Muhammad, who was born on December 31, 1953, resigned on health grounds. He did not give details.
Muhammad hails from Doguwa, Giade Local Government of Bauchi State.
His resignation comes in the wake of calls by 14 Supreme Court justices for investigation into allegations of mismanagement of funds against him.
The justices in a recent letter, which was leaked to the public, protested among other things the alleged non-payment of their legitimate entitlements for a prolonged period of time.