UBS Group AG

Prospectus • Mar 14, 2013

Financial Services Authority UK Listing Authority Document approved

UBS AG

Date: 6/03/2013

SUPPLEMENTARY PROSPECTUS DATED 6 MARGH 2013 TO THE BASE PROSPECTUS DATED 7 JANUARY 2013 OF UBS AG

for the issue of UBS ETC Notes (the "Notes") linked to the various UBS Bloomberg Constant Maturity Commodity Index ("CMCI") Indices

This supplementary prospectus (the "Supplementary Prospectus") constitutes a supplementary prospectus for the purposes of section 87G of the Financial Services and Markets Act 2000 (the "FSMA") and Article 16 of Directive 2003/71/EC as amended (the "Prospectus Directive") and should be read in conjunction with the Base Prospectus (the "Base Prospectus") of UBS AG, incorporated in Switzerland, as issuer (the "Issuer") dated 7 January 2013. Terms used in this document, unless otherwise stated, bear the same meanings as in the Base Prospectus. The purpose of this Supplementary Prospectus is to incorporate by reference the consolidated financial results of the UBS Group (the "Issuer Group") for the fourth quarter of 2012 and to reflect significant new information in respect of:

1. the Issuer Group's 2012 fourth quarter results;

$\overline{2}$ . the recent announcement of a fourth-quarter net loss; and

1. the Issuer's buy back of outstanding bonds in public tender offers.

and to amend the Summary of the Base Prospectus to take into account new information included in this Supplementary Prospectus.

This Supplementary Prospectus has been filed with the Financial Services Authority the ("FSA") and made available to the public in accordance with Rule PR 3.2 of the Prospectus Rules and Articles 14 and 16 of the Prospectus Directive. This document has been approved as a supplementary prospectus by the FSA under section 87A of the FSMA and Articles 13 and 16 of the Prospectus Directive.

The Issuer accepts responsibility for the information contained in this Supplementary Prospectus. To the best of the knowledge and belief of the Issuer, who has taken all reasonable care to ensure that such is the case, the information contained in this Supplementary Prospectus is in accordance with the facts and does not omit anything likely to affect the import of such information.

To the extent that there is any inconsistency between (a) any statement in this Supplementary Prospectus or any statement incorporated by reference into the Base Prospectus and (b) any other statement in or incorporated by reference into the Base Prospectus, the statements in (a) above will prevail.

Save as disclosed in this Supplementary Prospectus, there has been no other significant new factor. material mistake or inaccuracy relating to information included in the Base Prospectus which is capable of affecting the assessment of the Notes issued under the Base Prospectus since the publication of the Base Prospectus.

Any person who has agreed with an Offeror to buy or subscribe for Notes prior to publication of this Supplementary Prospectus may, in accordance with sections $87Q(4)-(6)$ of the FSMA, withdraw his acceptance before the end of two working days beginning with the first working day after the day of publication of this Supplementary Prospectus. Accordingly any such person wishing to exercise the statutory withdrawal rights contained in sections 87Q(4)-(6) of FSMA must do so by lodging a written notice of withdrawal with the appropriate Offeror during normal business hours (or by any other means as may be agreed with the appropriate Offer) so as to be received no later than 8 March 2013. Notice of withdrawal which is deposited or received after such date will not constitute a valid withdrawal.