The latest investment was 9,170,000 shares at a cost of 5.88p a share.
It brings Candy’s total shareholding in the firm to 25m shares, a 4.6 per cent stake.
Candy, who made his name in dealing in high-end flats, was appointed a non-executive director of the company last month.
Audioboom provides a social platform for audio content, such as radio shows or podcasts, to be streamed and shared online, either on its website or through its mobile app.
Major media names such as the BBC, Talksport, Absolute Radio, and the Guardian have recently agreed to publish content via the service.
The firm has also hired the comedian and former radio presenter Russell Brand as a flagship presenter of a podcast.
Shares in Audioboom closed up 15 per cent yesterday, at 8.2p