Signed a contract to audit the 2026 financial statements with E&Y

COTECCONS D{oe leap - Tq do - Hanh phuc

COTECCONS CONSTRUCTION THE SOCIALIST REPUBLIC OF VIETNAM

JOINT STOCK COMPANY Independence - Freedom - Happiness

Sñ/ No.: 307/2026/CV-CTD TP. Hâ Chi Minh, ngây 26 thâng 01 nâni 2026 Ho Chi Minh ciiy, Joniiur v !6, *02â

CONG BE THONG TINBAT THIS G

EXTRAORDINARY INFORMATION DISCLOSURE

Kinh giri/ To: - Uy Ban Ch*ng Khoan nhii nirñc/ State Securities Commission of Vietnam

- SP Giao dich Cbirng khoan Viet Nam/ S‹i' Giao dich Cbñ'ng khoan thñnh pho Ho ChiMinh/ Vietnam Exchange/ Hochiminh Stock Exchange

1. Ten to chic/Name of organization: Cñng ty Co phan Xay Dung Coteccons/ Coteccons Construction Joint Stock Company

   Ma chung khoan/ Stock code: CTD

   Dia chi/Address. 236/6 Dién Bién Phñ, P. Gia D|nh, TP. HCM

   Dien thoai lien he/ Tel.: (84) (28) 35142255 - Fax: (84) (28) 35142277 E-mail: bodsecretary@coteccons.vn

2. Noi dung thñng tin cñng bo/ Contents of disclosure:

   - Can cu Thir hgn kiem toan so 0011658650 O-10348118 E-69498888 0000 EL dirpc ky két vao ngay 23/0 1/2026 giâa Cong ty Co phan Xfiy ding Coteccons (Coteccons) vñ Cñng ty TNHHErnst & Young Viet Nam (E&Y Viet Nam), Coteccons dñ chpn E&Y Viet Nam la don vi thuc hien soat xét va kiem toan cac Bao cao tiii chinh cho nam tñi chinh 2026.

   Pursuant to Audit Engagement Letter No. 00.11.658650O- 1034811.8 E-69498888 0000 EL signed on 23 January 2026 between Coteccons Construction Joint Stock Company (Coteccons) and Ernst & Young Vietiiam Limited (E&Y Vietnam), Coteccons has selected E&Y Vietnam as the entity to conduct the review and audit of the financial statements for the fiscal year 2026.

3. Thfing tin nñy dii du'pc cñng bo trén trang thfing tin dien tñ' cña cñng ty vao ngñy 26/01/2026 tar dirdng dan: https://coteccons.vn/investor-relations-vn// This inforiiiation was piiblished on the company's website on Jaiiiiai'y 26, 2026, as in the link https://www.coteccons.vn/en/investor-relations/.

Chung tñi xin cain két cac thñng tin cong bo trén day lñ dung sq th{at va hoân toan chlti trach nhiem trtmc phap lueat ve noi dung cfc thñng tin dii cong bo/ We hereby certify that the information provided is trtie and correct and we bear the full responsibility to tJie law.

T‹ti lien dlitli kém7

Atr‹ic/ied r?ociinie•fs:

- Nhx myc 2/ As ifein 2

Dai dién tñ chirc faction representative

iyen cñng bñ thong tin

Av ñ:information disclosure

DINH THIHONG THAM