Tenaris S.A.

Transaction in Own Shares • Dec 26, 2025

Giovanni Sardagna Tenaris 1-888-300-5432 www.tenaris.com

Weekly Report (December 22, 2025 – December 26, 2025) on the Second Tranche of Tenaris Share Buyback Program.

Luxembourg, December 26, 2025. - Tenaris S.A. (NYSE and Mexico: TS and EXM Italy: TEN) ("Tenaris") announced today that pursuant to its Second Tranche of the USD1.2 billion Share Buyback Program announced on November 2, 2025, covering up to USD600 million to be executed in the open market, it has repurchased the following ordinary shares from December 22, 2025 to (and including) December 26, 2025:

Date	Trading Venue	Shares Purchased	Weighted Average Price (EUR)	Purchases in EUR	Reference FX	Purchases in USD
22-dic-25	MTA	656,671	16.3307	10,723,897	1.1710	12,557,684
22-dic-25	CEUX	456,433	16.3313	7,454,144	1.1710	8,728,803
22-dic-25	TQEX	55,421	16.3316	905,114	1.1710	1,059,888
22-dic-25	AQXE	53,545	16.3328	874,540	1.1710	1,024,086
23-dic-25	MTA	629,346	16.3693	10,301,953	1.1764	12,118,703
23-dic-25	CEUX	450,798	16.3760	7,382,268	1.1764	8,684,131
23-dic-25	TQEX	53,369	16.3702	873,661	1.1764	1,027,731
23-dic-25	AQXE	53,150	16.3702	870,076	1.1764	1,023,514
		2,408,733	16.3512	39,385,654		46,224,540

From December 22, 2025 to (and including) December 26, 2025, the Company has purchased a total of 2,408,733 ordinary shares for a total consideration of €39,385,654 equivalent to USD46,224,540.

As of December 26, 2025, the Company held in treasury 59,008,147 ordinary shares equal to 5.50% of the total issued share capital.

Tenaris intends to cancel treasury shares purchased under the Programs in due course.

Details of the above transactions, are available on Tenaris's corporate website under the Share Buyback Program Section https://ir.tenaris.com/share-buyback-program.

Some of the statements contained in this press release are "forward-looking statements". Forward-looking statements are based on management's current views and assumptions and involve known and unknown risks that could cause actual results, performance or events to differ materially from those expressed or implied by those statements. These risks include but are not limited to risks arising from uncertainties as to future oil and gas prices and their impact on investment programs by oil and gas companies.

Tenaris is a leading global supplier of steel tubes and related services for the world's energy industry and certain other industrial applications.