TGS - Changes in depreciation rates for tax purposes

Reference is made to the Q1 2013 Earnings Release (note 6) and the 2012 Annual
Report (note 25) regarding taxable depreciation of the multi-client library.

TGS received a letter from the Norwegian Tax Authorities in October 2011
questioning the Company's historical taxable depreciations of the multi-client
library. TGS has during 2011 to 2013 responded with documentation of the
Company's practice which refers back to a publication by Tax Authorities from
1993 regarding taxable depreciation profiles.

On 15 May 2013, TGS received a resolution from the Norwegian Tax Authorities
stating that depreciation rates for tax purposes should follow the depreciation
rates used in the financial statements. Further, the taxable revenue recognition
and depreciation should not commence until the final product is ready for
delivery to a client.  The resolution implies an increased taxable income by
approx. NOK 1.27 billion for the period up to and including 2010. The related
earlier tax payments of already recognized tax liabilities for TGS would amount
to approx. NOK 355 million (USD 61 million). While the resolution would have a
one-off cash effect and potentially impact the phasing of future tax payments,
there are no significant P&L effects related to the resolution.

TGS and its tax advisors do not agree with the resolution from the Norwegian Tax
Authorities with regards to historical depreciation rates for tax purposes. TGS
will consider filing a complaint to the complaints commission or issue a writ to
the relevant district court.


This information is subject of the disclosure requirements acc. to §5-12 vphl
(Norwegian Securities Trading Act)



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