Attorneys from MoloLamken are challenging a new U.S. Securities and Exchange Commission rule limiting shareholder proposals included in company proxy materials, which it claims would stifle the voice of smaller investors in corporate governance.

The firm filed suit Tuesday on behalf of shareholder advocates seeking to invalidate changes enacted by the SEC last September, which require investors to invest more money over a longer period of time to be eligible to submit proposals and restrict the use of shareholder representatives to present recommendations on behalf of investors.