 |  | | Volkswagen leaves door open on M&A as VW brand struggles |  | | WOLFSBURG, Germany (Reuters) - Volkswagen left the door open to a potential tie-up with Fiat Chrysler or another rival on Tuesday, as a drop in operating profit at its biggest car brand showed the challenges it still faces 18 months on from its emissions scandal. | |  |  |  | | Oil drops amid rising stocks, dragging on energy shares |  | | NEW YORK (Reuters) - Oil prices tumbled on Tuesday, weighing down energy shares in the wake of a report of rising crude stocks, while the U.S. dollar strengthened ahead of an expected Federal Reserve decision to raise interest rates. | |  | |  |  | | |  |  | Related Video | |  | | |  | | |  |  |  | Related News | |  | | |  | | |  |  |  |  |  | | Get a jump on the day with our early morning summary of key news developments for the US markets, as well as global market news. Register Today |  | |  |  |  | | The latest Reuters articles on M&A, IPOs, private equity, hedge funds and regulatory updates delivered to your inbox each day. Register Today |  | |  | | » » MORE NEWSLETTERS |  | |