Twitter Inc’s biggest shareholder, Elon Musk, has decided not to join its board, Chief Executive Parag Agrawal said late on Sunday.

Musk, who calls himself a free-speech absolutist and has been critical of Twitter, disclosed a 9.1% stake on April 4 and said he plans to bring about significant improvements at the social media platform.

His appointment to the board was to become effective on Saturday and would have prevented him from being a beneficial owner of more than 14.9% of common stock.