The drubbing comes as uncertainty surrounds Twitter's long-term growth and leadership. Chief Financial Officer Anthony Noto sparked a selloff late last month when he said on Twitter's earnings conference call that "sustained, meaningful" user growth would not come for a "considerable period of time."
Separately, Re/Code reported that former CEO Dick Costolo will likely step down from the social media company's board once his permanent replacement is hired, citing unnamed sources close to the company. A spokesman for Twitter did not immediately return an email from CNBC seeking comment.
Read MoreTwitter closes at record low amid growth concerns
In the second quarter, Twitter showed progress in monetization, as its $502 million in revenue topped the Street's estimates. Its advertising sales climbed 62 percent year over year to $452 million.
But investors soured as the company reported 304 million monthly active users in the quarter. That marked an increase of 2 million from the previous quarter and came in below expectations of 310 million.
Twitter co-founder and Square CEO Jack Dorsey currently leads the company on an interim basis after Costolo stepped down at the end of June. While Dorsey has maintained that he will not change Twitter's strategy, some investors have called for him to stay.
Early Twitter investor Chris Sacca on Friday urged the company's board to keep Dorsey as CEO, saying he has "product vision." In a string of tweets, Sacca also recommended Twitter name executive Adam Bain president and chief operating officer, while making co-founder Evan Williams chairman of the board.
In the last week, Noto and venture capitalist Peter Fenton have each acquired roughly 7,000 Twitter shares, according to SEC filings.
— CNBC's Robert Hum contributed to this report.