Goldman Sachs swung to a third-quarter loss as stiff markdowns in the value of its massive lending and investing portfolio forced the investment bank to turn in only its second quarter in the red since its 1999 initial public offering.

Like its peers, Goldman found revenue-generating opportunities to be scarce in the third quarter as choppy markets sidelined clients. Investment banking revenue slumped 33% from a year ago, adding to a disappointing capital markets performance seen across the Street during the period.