Employees from Northern Trust, Morgan Stanley and BMO Harris are joining Gary Hirschberg's new Chicago firm, Aaron Wealth Advisors. : A financial advisor at Goldman Sachs has left the investment bank's Private Wealth Management group to start his own firm and recruited executives from other top wealth managers to join him. Longtime advisor Gary Hirschberg, a vice president at Goldman Sachs who previously oversaw $1.4 billion in private and institutional client assets, said in a statement Monday he left the bank to found his own registered investment advisory business called Aaron Wealth Advisors.