TV and radio producer Ten Alps (LON:TAL) told investors it was not aware of a reason for the "sharp increase" in the shares in recent days.
Shares in the media group, founded by Sir Bob Geldof, have seen a near doubling since New Year's Eve - moving to 1.05p from 0.53p.
Today, they are up 20% at the time of writing.
"The board is not aware of any reason for the price movement," it said in Monday's brief regulatory filing.
Newsflow has been heavy in recent weeks at the firm, which has now largely completed a restructuring, and saw a loss before tax of £2.56mln for the 15 months to end June (2013: loss of £8mln).
On December 15, it announced former ITN boss Mark Wood as its chief executive.