As of March 2025, 66.15% is owned by Indian Promoters and 33.85% by Public.

Top five Promoters holding highest number of shares of Atmastco L company are Subramaniam Swaminathan Iyer (73.04 lakhs shares / 29.53%), Bodies Corporate (48.33 lakhs shares / 19.54%), Apex Steel And Technology India Private Limited (44.65 lakhs shares / 18.05%), G Venkataraman (35.83 lakhs shares / 14.49%) and Jayasudha Iyer (3.82 lakhs shares / 1.55%).