Goldman Sachs is trying to block a shareholder proposal for an independent chairman of its board from appearing on the proxy ballot, one year after fighting back against a similar proposal by another activist group that resulted in it naming a lead outside director.

CtW Investment Group, which works with pensions sponsored by a group of unions with 5.5 millon members and $200bn in assets, sent a letter to Goldman on Dec. 13 detailing its proposal, which calls on the board to adopt an independent chairman who hasn't been an executive officer of Goldman and hasn't had other affiliations or connections with the bank.