A major shareholder of Singapore-listed medical device group Biosensors has agreed to sell its entire stake in the company for US$312.3 million (S$390.2 million).

Wellford, which owns 21.7 per cent of Biosensors, will sell its shares to CB Medical Holdings, said Wellford's parent company Shandong Weigao Group Medical Polymer Company on Friday.

The price works out to $1.05 a share and represents a premium of about 11.7 per cent to Thursday's closing price of 94 cents a share, the company said.

It expects the sale to be completed on Dec 20 or another date no later than Feb 28 next year.

Shandong Weigao's main business is the research and development, production and sale of single-use medical devices. CB Medical Holdings is an investment holding company incorporated in Bermuda.

Shandong Weigao said it is selling the Biosensors shares to focus on its three principal business units: medical consumables, blood purification and orthopedic products. This will allow the group to "remain competitive and maintain its leading position in single use medical devices", it added.