Steve Ballmer takes 4% stake in Twitter

Former Microsoft Corp chief executive Steve Ballmer had taken a 4-per cent stake in Twitter Inc, according to his spokesman, which made him the third-biggest individual shareholder in the social media company.

Ballmer's stake was worth over $800 million on the basis of Twitter's $21-billion market value.

Only co-founder Evan Williams and Saudi billionaire Prince Alwaleed bin Talal hold higher stakes among individual investors.

Twitter shares surged 5.6 per cent to $31.34 yesterday, hours after Ballmer tweeted from a non-verified account that he had built up his stake over the past several months.

His tweet lauded Twitter's new 'Moments' feature, which curated the best tweets of the day, as also Dorsey's appointment as permanent CEO last week.

"Good job @twitter, @twittermoments innovation, @jack Ceo, leaner, more focused," the tweet said. "Glad I bought 4% past few months."

Ballmer, who bought the Los Angeles Clippers basketball team retired as Microsoft CEO in February 2014, has a personal fortune of about $21.5 billion, making him the 35th richest person in the world, according to Forbes magazine.

According to commentators, his backing as an investor was no guarantee of success for Twitter. He is known to have laughed at Apple Inc's first iPhone, and shares of Microsoft fell during the 14 years of his leadership.

Twitter closed just over $21 billion yesterday.