GlaxoSmithKline announces sale of shares in Quest Diagnostics Inc.

GlaxoSmithKline plc (the “Group”) announces today that it has sold 5,749,157 shares of common stock, par value of $0.01 per share (the “Shares”), of Quest Diagnostics Inc. (“Quest”).

The sale of the Shares was achieved partly through market sales under Rule 144 of the U.S. Securities Act of 1933, and, partly through a sale directly to Quest. Details of these transactions are provided below.

During the period 17^th March to 19^th March 2009, 1,237,500 Quest shares were sold in the market, as follows:

 Date                            Number of         Aggregate    Average

                                    Shares                Price             Price

17th March 2009         500,000           $22,749,150    $45.50

18th March 2009         500,000           $22,852,050    $45.70

19th March 2009         237,500           $10,541,960    $44.39

Total                         1,237,500          $56,143,160    $45.37   

In addition to the market sales detailed above, on 19^th March 2009, 4,511,657 Quest shares were sold back to Quest for $44.33 per share, for an aggregate price of approximately $200 million. 

The Shares were sold as part of a gradual reduction in the Group’s holding and to take advantage of Quest's recently expanded share repurchase programme. The Group originally acquired the Shares following the sale of the Group’s clinical laboratories business to Quest in 1999.

Following the sale of the Shares, the Group holds 30,755,151 shares of common stock in Quest, being approximately 16.5% of the issued share capital of Quest, with a market value of approximately $1.36 billion.

S M Bicknell

Company Secretary

19 March 2009

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