Twitter CEO Parag Agrawal on April 11 tweeted that Elon Musk has decided not to join the company’s board.

While Agrawal didn’t mention why Tesla CEO refused to take the board seat, he noted that Musk remains the largest shareholder of Twitter, and the company will be open to his input.

In a brief note to the company, Agrawal wrote that “The Board and I had many discussions about Elon joining the board, with Elon directly. We were excited to collaborate and clear about the risks… We announced on Tuesday that Elon would be appointed to the Board contingent on a background check and formal acceptance. Elon’s appointment to the Board was to become officially effective 4/9, but Elon shared that same morning that he will no longer be joining the board. I believe this is for the best… Elon is our biggest shareholder and we will remain open to his input.”

Last week, an SEC (Securities and Exchange Commission) filing revealed that Tesla’s founder has bought 73,486,938 shares or 9.2 percent stake in a microblogging site via Elon Musk Revocable Trust, Reuters reported.

The SEC filing came days after Musk had posted a poll on Twitter, asking its users whether they believe that the social media platform “rigorously adheres” to the principle of free speech. After a public exchange over the poll on Twitter, Agrawal officially welcomed the Tesla CEO to the board.

This weekend also, Musk outlined a series of suggestions for Twitter. The Tesla and SpaceX CEO said that the company should include an authentication checkmark as a feature of its Twitter Blue premium subscription service, which costs $3 a month.

Twitter adds a checkmark logo next to a user name when the account has been verified authentic, notable, and active.

Musk also suggested Twitter make the authentication checkmarks of premium subscriber accounts different than those granted to official accounts belonging to public figures, for example.

Such a move, Musk said, would massively expand the pool of verified user accounts and discourage the proliferation of spam-bot accounts, making them too expensive to maintain.

Musk also shared ideas for how Twitter should charge for its subscription membership, saying the fee should be proportionate to affordability and in local currency and adding: Maybe even an option to pay in Doge? Referring to the Dogecoin cryptocurrency.

And no ads, Musk tweeted. The power of corporations to dictate policy is greatly enhanced if Twitter depends on advertising money to survive.