Glaxosmsc 5.25% Regulatory News (AG99)

Publication of Supplementary Prospectus

The following Supplementary Prospectus dated 5 December 2012, supplementing the Base Prospectus dated 5 September 2012, has been approved by the UK Listing Authority and is available for viewing:

GlaxoSmithKline plc, GlaxoSmithKline Capital plc and GlaxoSmithKline Capital Inc. £15,000,000,000 Euro Medium Term Note Programme

A copy of the Supplementary Prospectus has been submitted to the National Storage Mechanism and will shortly be available for viewing at:

http://www.morningstar.co.uk/uk/NSM.

The Supplementary Prospectus will also be available for viewing at:

http://www.gsk.com/reports-and-publications.html

For further information, please contact:

GlaxoSmithKline plc

980 Great West Road

Brentford

Middlesex

TW8 9GS

United Kingdom

Enquiries:

BASIS ON WHICH YOU MAY ACCESS THE SUPPLEMENTARY PROSPECTUS AND BASE PROSPECTUS

Please note that the information contained in the Supplementary Prospectus and the Base Prospectus may be addressed to and/or targeted at persons who are residents of particular countries (specified in the Base Prospectus) only and is not intended for use and should not be relied upon by any person outside these countries and/or to whom the offer contained in the Base Prospectus is not addressed. Prior to relying on the information contained in the Base Prospectus you must ascertain from the Base Prospectus whether or not you are part of the intended addressees of the information contained therein.

Your right to access this service is conditional upon complying with the above requirements.