Yes---if the issuer is an SEC reporting registrant: https://www.sec.gov/answers/sched13.htm https://www.sec.gov/divisions/corpfin/guidance/reg13d-interp.htm Officers, directors, and affiliates of said issuer must file applicable Forms 3,4,5... as to consequences: https://www.morganlewis.com/pubs/securities_lf_sec_targetscorporateinsiders_18sept14