Amid a major downsizing drive announced by Twitter earlier this month, Jack Dorsey announced Thursday he would devote the shares to the staff equity pool because he wanted to "directly invest in our people."

A third of Dorsey's personally-held stock amounts to "exactly one percent" in the micro-blogging website, and was worth $197 million (177 million euros) at the end of July.

The move will increase the number of shares available to reward workers, and is seen as an effort to boost staff morale after a series of high-level departures over the past few months.

Former Twitter chief Dick Costelo resigned in June and Dorsey has returned as interim CEO only to see himself forced to lay off 336 employees - about 8 percent of its workforce - amid slumping earnings.

In a tweet following the announcement, Dorsey said: "I'd rather have a smaller part of something big than a bigger part of something small."

Twitter has not yet turned a profit in its history and is struggling to expand its user base, lagging behind rival networks such as Instagramm and Facebook. Under efforts to revive growth at the social network, Dorsey outlined his "roadmap" for more users and revenue earlier this month. He rolled out a "buy now" button that allows users to make purchases, and a feature that shows users the site's best tweets and content as curated by a Twitter team.

Last week, former Microsoft CEO Steve Ballmer said he had taken a 4 percent stake in Twitter, making him the third-biggest individual shareholder in the social media company. Ballmer now owns more of Twitter than Dorsey, who has a 3.2 percent stake, according to Thomson Reuters data.

uhe/cjc (AFP, dpa, Reuters)