The global reach of Goldman Sachs Group, through a network of former officials, could help foster cooperation as U.S. officials reach out to foreign powers to calm financial markets. But it could also promote conflicts of interest.

When U.S. Treasury Secretary Henry Paulson chose former Allstate Chairman Edward M. Liddy to head American International Group Inc. after the government’s bailout of the insurance giant, he was turning to an old buddy he knew he could trust.