Number of issued shares: 1,180,536,830

Each share is of par value U.S.$ 1.00 per share and entitles the holder thereof to one vote at Tenaris’s general shareholders’ meetings.

Registered major holders:

The following holders have notified the Company of holdings in excess of 5% of the Company’s capital or the rights to vote such shares.

   San Faustín N.V. ⁽¹⁾   713,605,187 shares (60.4%)

⁽¹⁾ San Faustín N.V. owns all of its shares in the Company through its wholly-owned subsidiary I.I.I. Industrial Investments Inc.  Rocca & Partners S.A. controls a significant portion of the voting power of San Faustín N.V. and has the ability to influence matters affecting, or submitted to a vote of the shareholders of, San Faustín N.V., such as the election of directors, the approval of certain corporate transaction and other matters concerning the company’s policies. There are no controlling shareholders for Rocca & Partners.

Important notice under Luxembourg law

Under Luxembourg legislation implementing the EU Transparency Directive, investors in Tenaris’s securities who directly or indirectly own or otherwise control 5% or more of the shares of Tenaris’s capital or the rights to vote such shares should give notice thereof to Tenaris March 19, 2008, for further publication to the market. The number of shares and votes set forth above should be used for purposes of determining whether an investor reaches or exceeds such threshold. In addition, investors should notify Tenaris and the Luxembourg securities commission (the CSSF) on an ongoing basis whenever their direct or indirect ownership or other control rights over shares of Tenaris’s capital or rights to vote such shares either reaches, exceeds or falls below any of the following thresholds: 5%, 10%, 15%, 20%, 25%, 33.33%, 50% and 66.66%.

Any notification to Tenaris under the Luxembourg Transparency Law or its regulations should be made in writing and sent electronically to investors@tenaris.com or by letter addressed to:

Tenaris S.A.
46A, Avenue John F. Kennedy
L-1855 Luxembourg
Att: Company Secretary

This information does not constitute legal advice. Investors are encouraged to seek advice of counsel in connection with their obligations under applicable law and the consequences of failing to comply with any such obligations.