The logo of Goldman Sachs is displayed in their office located in Sydney, Australia, May 18, 2016. REUTERS/David Gray/File Photo

NEW YORK (Reuters) - Goldman Sachs economists said on Friday they now expect the U.S. Federal Reserve to announce a plan to shrink its $4.5 trillion balance sheet at its September policy meeting, earlier than their prior view for such a move in December.

They changed their forecast on a third U.S. rate increase in 2017 to occur in December from September, while they raised their estimate on a possible rate hike later this month to 90 percent from 80 percent.