hVIVO PLC, a specialist in the field of human challenge clinical trials for infectious and respiratory diseases, said certain directors have agreed to sell shares to meet institutional demand.
Involved in the secondary placing, managed by Cavendish Capital Markets and Peel Hunt, are Cathal Friel, hVIVO's co-founder and chairman, Pamela Iyer, Friel's spouse, and Brendan Buckley, another co-founder and non-executive director of the business.
In all, they are selling 14 million shares for 28p each - which is around a quarter of their combined investment in hVIVO.
"Following a series of meetings with both new and existing institutional investors, it became apparent that demand for ordinary shares was in excess of those readily available for sale," the company said in a press release.
"The selling shareholders recognise the strategic importance to hVIVO of a strong and supportive institutional shareholder base, and have therefore decided to release a portion of their own holdings in order to help satisfy this demand."
The share sale will done via a book-building process.