The Securities and Exchange Commission in Washington, D.C. Reuters After Senator Elizabeth Warren sent a letter to the Securities and Exchange Commission on Friday, the regulator said it would keep an eye on the situation. In a statement, the agency said: "The Commission is closely monitoring and evaluating the extreme price volatility of certain stocks' trading prices over the past several days. Our core market infrastructure has proven resilient under the weight of this week's extraordinary trading volumes." It added: "Nevertheless, extreme stock price volatility has the potential to expose investors to rapid and severe losses and undermine market confidence."