The group, which took a stake in Aspen in 2009, said yesterday that it was planning to reduce its 19 per cent holding to cash in on a rise in its value, but vowed to remain a “significant shareholder”.
Glaxo is left with a 12.4 per cent interest in the South African firm after selling 28.2 million shares at 250 rand (£15.21) each.
The maker of Aquafresh toothpaste and Panadol painkillers said its “close relationship” with Aspen would not be affected by the sale, and it will retain a seat on the firm’s board.
In September. Aspen agreed to pay about £700m for two of Glaxo’s thrombosis treatments and a manufacturing site in France.