About half its shares will be sold in the flotation, which will value Healthcall at pounds 70m. Venture capital backers are selling shares worth pounds 10m.
Healthcall's main business is designed to help general practitioners with their out-of-hours responsibilities. They use Healthcall's doctors and communications network as a substitute for their own services.
The firm operates clinics that open all night and at weekends to alleviate pressure on hospitals' accident and emergency units. It also has a mobile opticians' service for the elderly. Money from the float will allow Healthcall to fund the new developments.
Most GPs who use Healthcall also work for the company on a part-time basis. Maurice Henchey, chief executive, estimated yesterday that GPs could pay for the Healthcall service by working three six- hour shifts a month.
Healthcall has a fleet of cars and concentrates operations in urban areas. Doctors are taken to calls by a driver who can double as a security minder. It wants money from the float to repay debts incurred when the management staged a buyout of the business in 1990.
Seventy directors and senior managers are liquidating about pounds 2m between them in the issue, equivalent to 25 per cent of their holdings. Mr Henchey said he was selling few shares. After the issue he will own 12 per cent of the company.Reuse content