The Bulls and their CEO, Alfons Meyer, are set to part ways, it was confirmed in a statement from the union on Friday.
Meyer will be leaving his post at the end of May 2020, having joining the Pretoria-based union on 1 January, 2019.
His contract was due to expire at the end of 2020.
"We would like to thank Alfons for his great contribution to the company," Blue Bulls board chairperson Pieter Uys said.
"Over the past year he has been instrumental in the restructure of the Blue Bulls Company, and has laid a strong foundation on which the company can build and become the world class team again that it once was.
"We respect Alfons' decision to step down and wish him well in his future endeavours."
When contacted by Sport24, the Bulls confirmed that Meyer was stepping down because of "personal reasons".
He was still on good terms with the union.
"I thoroughly enjoyed my time with the Bulls, it has been the highlight of my professional career," Meyer said.
"2019 was an exceptional year to be part of the Bulls Super Rugby campaign, and to play a major role in the equity transaction which saw Mr Patrice Motsepe become part of the Bulls family as an investor was a privilege.
"I wish the staff and players all the best, especially during these extraordinary times - I will remain a loyal supporter forever!"
The Bulls in late March confirmed the appointment of former Springbok coach Jake White as director of rugby at the union until the 2023 Rugby World Cup in France.
- Compiled by Lloyd Burnard