X0508 4 2024-03-08 0 0001856995 Mountain & Co. I Acquisition Corp. MCAAU 0001480933 Boersch Cornelius C/O MOUNTAIN & CO. I ACQUISITION CORP. 4001 KENNETT PIKE, SUITE 302 WILMINGTON DE 19807 1 1 1 0 Chief Executive Officer 0 Class A ordinary shares 2024-03-08 4 C 0 4925000 A 4925000 I By Mountain & Co. I Sponsor LLC Class B ordinary shares 2024-03-08 4 C 0 4925000 0 A Class A ordinary shares 4925000 150000 I By Mountain & Co. I Sponsor LLC Converted on a one-for-one basis. Each Class B Ordinary Share will automatically convert into Class A Ordinary Shares at the time of the Issuer's initial business combination or earlier at the option of the reporting person as described in the section entitled "Description of Securities" of the Issuer's registration statement on Form S-1 (Reg. No. 333-259034). The reporting person is the controlling shareholder of Mountain & Co. I Sponsor LLC via his direct holdings and the holdings of two entities (of which the reporting is the controlling shareholder), Mountain Partners AG and Conny & Co. Advisory AG. Therefore, the reporting person may be deemed to have indirect beneficial ownership of the shares held by Mountain & Co. I Sponsor LLC. The reporting person directly owns additional 20,000 Class B ordinary shares. /s/ Dr. Cornelius Boersch 2024-03-08