The Broadcast Club sent a survey to every director of corporate communications at each FTSE 100 company.
The survey, run by Baron & Hopkins, asked for the number of spokespeople each company had, plus how many were female and media-trained for broadcast news.
Of the 650 total media spokespeople employed, 435 (67 per cent) were trained for broadcasting. Of those broadcast media trained, 197 (45 per cent) were female. However, only 14 companies filled out the survey.
The Broadcast Club said it raises questions about transparency and concerns that corporations may have something to hide.
The non-proft organisation will host a discussion on the issue of gender representation in broadcast media spokespeople at Portcullis House in Westminster at 6.30pm this evening.
The event will be hosted by former TV journalist Adam Holloway MP and the panel will include culture minister Nigel Adams and Broadcast Club founder Kerry Hopkins.
Hopkins said she conducted the research after speaking to a number of companies over the past six years and suspected there may not be enough female spokespeople.
Research conducted by the Expert Women Campaign in June last year showed there are 2.5 men to every female expert interviewed on television.
"I am thrilled that out of those 14 companies surveyed, 45 per cent of media spokespeople are female. But, why did 86 per cent of companies not fill in the survey?"
Hopkins added: "The lack of transparency that UK publicly listed corporations have displayed is concerning, which is ironic since it is their media spokespeople who are public-facing. One of our goals at the Broadcast Club is to get more spokespeople broadcast-ready."