Sunoco swung to a first-quarter loss as margins for oil-refinery products continued to be weak, but signaled hope that the summer driving season would improve results.

General Motors swung to a $3.25 billion net loss in the first quarter despite strong earnings overseas. Results were hurt by continuing weakness in its core North American operations and charges related to lending arm GMAC and former unit Delphi. (Conference call transcript)

Procter & Gamble posted a 7.9% rise in profit and said private-label competition hasn’t made inroads despite the slow economy. Colgate-Palmolive’s net income fell 4.1%, reflecting gains a year earlier. (P&G conference call transcript)

Prudential Financial’s first-quarter net income dropped 94% on large investment losses.

Germany’s SAP said its first-quarter net profit fell 22% due to costs associated with its takeover of French software firm Business Objects.

Sanofi-Aventis posted drops in both profits and sales in the first quarter as a weak dollar and competition from low-cost generics hurt the French drug maker’s sales, continuing a negative streak of drug-industry earnings.

Operating profit at Volkswagen’s core VW passenger-car brand rose 19% in the first quarter, but the auto maker added that the current exchange rate between the dollar and the euro is making it “extremely difficult to break even” in North America.