UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER
PURSUANT TO RULE 13a-16 OR 15d-16
UNDER THE SECURITIES EXCHANGE ACT OF 1934

Date of Report: March 1923, 2026

Commission File Number: 001-39570

TIM S.A.
(Exact name of Registrant as specified in its Charter)

João Cabral de Melo Neto Avenue, 850 – North Tower – 12^th floor
22775-057 Rio de Janeiro, RJ, Brazil
(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F ☒ Form 40-F ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1).

Yes ☐ No ☒

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7).

Yes ☐ No ☒

TIM S.A.

Publicly-~~Held~~held ~~Company~~company

CNPJ/MF 02.421.421/0001-11

NIRE ~~333~~33.~~0032463-1~~300.324.631

~~MINUTES~~Notice OFto ~~THE~~the ~~BOARD OF DIRECTORS’ EXTRAORDINARY MEETING~~Market

~~HELD~~Clarifications ONRegarding ~~MARCH~~the ~~18TH,~~Public ~~2026~~Offer Addressed to Telecom Italia S.p.A.

~~DATE,~~TIM ~~TIME~~S.A. ~~AND~~("TIM" ~~PLACE~~or "Company") (B3: ~~March~~TIMS3; ~~18th,~~NYSE: ~~2026~~TIMB), atin ~~4.10~~accordance ~~p.m.~~with ~~Due to~~ the ~~importance~~provisions ~~and~~of ~~urgency~~CVM ofResolution ~~the~~No. ~~matter~~44/21, oninforms ~~the~~its ~~Agenda~~shareholders, the ~~meeting~~market ~~was~~in ~~held~~general inand ~~the~~other ~~form~~interested parties that it has become aware of a ~~virtual~~press ~~deliberative circuit~~release issued today by its indirect parent company, asTelecom ~~provided~~Italia S.p.A. ("Telecom Italia"), in which the ~~3rd~~Board ~~paragraph~~of Directors of ~~Section~~that 25company registered the launch of ~~TIM~~a Public Offering promoted by Poste Italiane S.p.A.~~’s By-laws (“Company”)~~.

~~PRESENCE:~~TIM ~~The~~clarifies ~~Board~~that ofsuch ~~Directors’ Meeting~~discussions ofand ~~the~~evaluations ~~Company~~take ~~was~~place ~~held~~exclusively within ~~with~~ the ~~presence~~scope of ~~Messrs.~~Telecom ~~Nicandro~~Italia ~~Durante,~~and ~~Adrian~~that ~~Calaza,~~after ~~Alberto~~consulting ~~Mario~~directly ~~Griselli,~~with ~~Alessandra~~the ~~Michelini, Claudio~~management ~~Giovanni~~of ~~Ezio~~its ~~Ongaro~~indirect parent company, ~~Denísio~~it ~~Augusto~~was ~~Liberato~~informed that, ~~Delfino~~so far, ~~Flavia~~there ~~Maria~~is ~~Bittencourt,~~no ~~Gesner~~additional ~~José~~information deon ~~Oliveira~~the ~~Filho~~subject, ~~Gigliola~~ ~~Bonino~~other ~~and~~than ~~Leonardo~~that dealready ~~Carvalho~~publicly ~~Capdeville~~disclosed.

~~BOARD:~~Reiterating ~~Mr.~~its ~~Nicandro~~posture ~~Durante~~of –diligence and transparency, the Company ~~Chairman;~~continues to closely monitor developments and ~~Mrs.~~will ~~Fabiane~~keep ~~Reschke~~the –market ~~Secretary~~informed under the terms of the applicable regulations.

~~AGENDA:~~ Rio Tode ~~resolve~~Janeiro, on23 ~~the~~March ~~payment proposal of the Company’s interest on shareholders’ equity (“IE”)~~2026.

~~RESOLUTIONS:~~TIM Upon the review of the material presented and filed at the Company’s head office, and based on the information provided and discussions of the subject included on the Agenda, the Board Members, unanimously by those present and with the abstention of the legally impeded, decided to register the discussions as follows:S.A.

~~CONT.~~Vicente OFde ~~MINUTES~~Moraes ~~OF THE BOARD OF DIRECTORS’ MEETING OF TIM S.A.~~Ferreira

~~March~~Investor ~~18th,~~Relations ~~2026~~Officer

Approved, based on the Section 46, 3rd and 4th paragraphs, of the Company’s By-laws, on the favorable opinion of the Fiscal Council, and on the favorable evaluation of the Statutory Audit Committee, the distribution of R$390,000,000.00 (three hundred and ninety million reais) as Interest on Shareholders’ Equity ("IE"), at R$0.1632708888 (zero point one, six, three, two, seven, zero, eight, eight, eight, eight cents) of gross value per share. The payment will be made until April 30th, 2026, without the application of any monetary restatement index, considering the date of March 23rd, 2026, as the date for identification of shareholders entitled to receive such values. Therefore, the shares acquired after said date will be traded ex-direito of IE distribution. The withholding of Income Tax will be of 17.5% (seventeen point five percent) on the occasion of the credit of the IE, except for the shareholders who have differentiated taxation or who are exempt from said taxation. The gross amount per share may be modified due to the variation in the number of treasury shares.

CLOSING: With no further issues to discuss, the meeting was adjourned, and these minutes drafted as summary, read, approved and signed by all attendees Board Members.

I herein certify that these minutes are the faithful copy of the original version duly recorded in the respective corporate book.

Rio de Janeiro (RJ), March 18th, 2026.

FABIANE RESCHKE

Secretary

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

	TIM S.A.
Date: March 19, 2026	By:	/s/ Alberto Mario Griselli
Date: March 23, 2026	By:	/s/ Alberto Mario Griselli
		Alberto Mario Griselli
		Chief Executive Officer, Chief Financial Officer and Investor Relations Officer

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