X0609 4 2026-05-01 0 0002109876 Mountain Crest Acquisition 6 Corp. MCAH 0001811534 Liu Suying false C/O MOUNTAIN CREST ACQUISITION 6 CORP., 524 BROADWAY, 11TH FLOOR, NEW YORK NY 10012 1 1 1 0 CEO and CFO 0 Ordinary shares 2026-05-01 4 P 0 25000 10 A 2982143 I See Footnote Rights 0 2026-05-01 4 P 0 25000 A Ordinary Shares 6250 25000 I See Footnote The reporting person acquired units, consisting of shares and rights. The rights automatically convert into one-fourth (1/4) of one ordinary share upon the consummation of the registrant's initial business combination, as described in the registrant's prospectus initially filed with the Securities Exchange Commission on April 6, 2026. Dr. Suying Liu controls Mountain Crest Holdings 6 LLC. As such, he may be deemed to have or share beneficial ownership of the securities held directly by Mountain Crest Holdings 6 LLC. Suying Liu disclaims any beneficial ownership of the reported shares other than to the extent of any pecuniary interest he may have therein, directly or indirectly /s/ Suying Liu Managing Member 2026-05-05