John Mack, the former chief executive of Wall Street firm Morgan Stanley (NYSE:MS), has joined the board of global commodities giant Glencore Xstrata (LON:GLEN), according to published reports.

The company formed when predecessor firms Glencore and Xstrata recently merged. Mack joins former BP Chairman Tony Hayward on the company's board. 

Hayward is also currently serving as Glencore Xstrata's interim chairman as the company looks for a permanent chief.

Mack ended his tenure as Morgan Stanley CEO in 2009 but remained chairman until in 2011. He is currently an adviser to the company.