In reversal, Elon Musk will not join Twitter's board

Musk informed Twitter of his decision on April 9, the day his board membership was scheduled to take formal effect.

Billionaire entrepreneur Elon Musk has decided not to join Twitter's board of directors after having purchased a 9.2% stake in the social media platform, making him its largest shareholder.

Twitter CEO Parag Agrawal announced Sunday that Musk has decided not to join the board, a message Musk shared with the board Saturday, the day Musk's board membership was set to become official.

"I believe this is for the best," Agrawal wrote. "We have and will always value input from our shareholders whether they are on our Board or not. Elon is our biggest shareholder and we will remain open to his output."

At the time of the initial announcement that Musk would join the board, Agrawal and outgoing board member and former CEO Jack Dorsey praised the Tesla founder and welcomed his input.

Musk's stock purchase that was announced last week is worth as estimated $3 billion.

Agrawal warned his employees that "There will be distractions ahead," and encouraged them to stay focused. "The decisions we make and how we execute is in our hands, no one else’s. Let’s tune out the noise, and stay focused on the work and what we’re building," he wrote.

Why Musk, an open critic of Twitter, decided not to take a seat on the board remains unclear.

Later on Sunday, Musk tweeted the giggling emoji. Prior to the announcement, he spent the weekend tweeting suggestions about how to improve the company – including one poll in which he asked his followers if Twitter headquarters in San Francisco should be turned into a homeless shelter "since no one shows up anyway."