Union officials, state regulators and people who lost retirement savings in the collapse of Enron Corp. urged the Securities and Exchange Commission on Wednesday to support the position of shareholders suing Wall Street banks for damages in a case before the Supreme Court.

The Enron shareholders’ $40 billion lawsuit contends that Merrill Lynch & Co., Credit Suisse Group and Barclays PLC should be held equally liable as Enron as participants in the energy company’s accounting fraud. Thirty states took the shareholders’ side.