Mek Yam @ Mariam Hassan, is currently the Head Corporate Secretarial Domestic & Listed, Group Secretarial and Board Governance (GSBG), PETRONAS. She is a Chartered Company Secretary from the Institute of Chartered Secretaries & Administrators, United Kingdom and currently a Fellow of Malaysian Institute of Chartered Secretaries & Administration.

Mariam has 26 years' experience in corporate secretarial & board governance and her exposure spans across various industries such as telecommunication, shipping, finance and oil & gas.  She first joined PETRONAS in 1999 and had a stint with MISC Berhad from 2005 until 2006.  She later joined Kuwait Finance House (Malaysia) Berhad in November 2006 where she served as the Head Corporate Secretarial Department and was the Company Secretary of the foreign Bank for 5 years. She re-joined PETRONAS in November 2011 as Head, Corporate Secretarial of PETRONAS Chemicals Group Berhad.  She has served various units within GSBG including the listed unit and Board Governance prior to being appointed to her current position in May 2021.  She is also the Company Secretary for several companies within PETRONAS Group including PETRONAS Dagangan Berhad, PETRONAS Gas Berhad, MLNG Group and PETRONAS Refinery and Petrochemical Corporation Sdn Bhd.  She is also the External Advisor to Kolej University Polytech MARA for the Bachelor of Corporate Administration Program.