Goldman Sachs Group Inc. said fourth-quarter net income dropped 19% on muted trading revenue, though strong investment-banking results and lower expenses helped the Wall Street firm beat analysts' expectations.

Despite the better-than-expected earnings, shares fell 2.2% in early afternoon trading, erasing some of the gains from recent days as investors focused on the firm's tough year in fixed income, currencies and commodities trading, its worst in that business since 2008.

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