Securities and Exchange Commission Executive Director Diego Tomas Ruiz will leave the agency and return to the private sector. Ruiz became the executive director in August 2006 to oversee the agency's strategy, policies and procedures. Ruiz follows several directors who have left the agency, which may be experiencing funding problems. Rep. Barney Frank (D-Mass.) introduced a bill this week to provide an additional $131 million to the SEC as it takes on more responsibilities under Dodd-Frank. "Diego has been a steady hand at the Commission over the last several years, and I have greatly valued his commitment and public service," SEC Chairman Mary Schapiro said. "He has provided guidance and counsel through challenging times at the agency and in the financial industry." Before he joined the SEC, Ruiz was the deputy chief for strategy and policy at the Federal Communications Commission. "The job of safeguarding the nation's financial markets is a high calling, and I am deeply grateful to the SEC's dedicated men and women for their tireless efforts, often under extraordinary pressure, on behalf of America's investors," Ruiz said. Write to Jon Prior. Follow him on Twitter: @JonAPrior