Twitter interim Chief Executive Jack Dorsey joined other insiders in buying more shares in the company in a show of confidence in the stock, which traded at a record-low last week.
Dorsey, who stepped in as interim CEO on July 1, has been candid about the problems faced by the microblogging website.
User growth in the second quarter increased at the slowest pace since the company went public in 2013.
"Investing in @twitter's future," Dorsey tweeted on Monday, after disclosing he had bought 31,627 shares, worth about $875,000 at $27.67 per share.
Dorsey now owns about 21.9 million shares, or about 3 percent of Twitter.
Separately, director Peter Currie disclosed he had bought and 9,200 shares worth about $249,000 at $27.03.
Twitter's shares were up 6.6 percent at $28.83 at midday. The stock fell to a record low of $27.82 on Aug. 7 — just shy of the IPO price of $26.
CFO Anthony Noto and another director, Peter Fenton, disclosed share purchases in the company last week.
Twitter clinched a multiyear partnership on Monday with the National Football League to deliver video and other content to NFL fans on a daily basis.