LONDON ( TheStreet) -- GlaxoSmithKline ( GSK - Get Report) said Wednesday it sold its entire stake in Quest Diagnostics ( DGX - Get Report) for $1.7 billion.

The stake of about 30.76 million shares was acquired by GlaxoSmithKline as partial consideration for the sale of its clinical laboratories business in 1999. The U.K. drugmaker said it has been gradually reducing its stake in stages.

After taxes, GlaxoSmithKline expects proceeds of about $1.1 billion from the sale of its stake in Quest, the U.S. life sciences company.

"While we have been pleased with our investment in Quest Diagnostics, we have been considering the sale of our remaining position in the company for some time," said Julian Heslop, GlaxoSmithKline's chief financial officer, in a statement. "We have decided that now is a good time to take advantage of favorable market conditions, thereby releasing funds from one of our non-core assets. "

GlaxoSmithKline reports full-year earnings Thursday.

-- Written by Joseph Woelfel

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