Twitter shares closed 8.4 per cent lower, at $24.67 in late morning trading, after rumours circulated that interim chief executive and founder Jack Dorsey will be appointed to the role permanently.
Yesterday technology news site Re/code reported that Dorsey would be named as the company's full-time chief exec as soon as today.
Dorsey led the company from its inception, but was ousted in 2008, replaced by fellow co-founder Evan Williams.
However, he was dragged back in in June after the departure of Dick Costolo, another co-founder, in June.
Re/code suggested that if Dorsey does come back to Twitter full-time, he will be expected to resign from the role of chief executive of Square, the online payments company he founded in 2009.
Twitter shares have fallen in recent months after quarterly results suggested growth is stalling.