The move pushed the Peter Thiel-backed video network down as much as 12%, before trimming losses by half, as traders discussed whether Rumble will now have to compete with Twitter for users seeking conservative media personalities. Investors had snapped up shares of Rumble and other stocks as speculation over Carlson's next landing spot spread last month.
A Rumble representative did not respond to a Bloomberg News emailed request for comment.
The platform, which emerged as a right-wing alternative to YouTube and claims to "create technologies that are immune to cancel culture," is seen as a competitor to social-media firms like Twitter and Facebook.
Rumble rallied 6% on the day Carlson was ousted from Rupert Murdoch's Fox empire and had gained 17% through Tuesday's close. Digital World Acquisition Corp., the blank-check firm taking Donald Trump's media company public, shook off losses to rise 1.1%. While Class A Fox shares dipped 1.6%.
In the video Carlson tweeted to announce his plan, he added that "there aren't many platforms left that allow free speech. The last big one remaining in the world — the only one — is Twitter."