Duke ( DUK) and ExxonMobil ( XOM) went their separate ways again Thursday. The energy giants were once partners in a widely watched trading venture. But that operation, Duke Energy Trading & Marketing, began winding down as the merchant-energy industry sputtered toward oblivion. And now, latest-quarter results show that Duke and Exxon are moving in very different directions once more. Duke has seen its stock soar since crowning a new leader, but the company handily missed first-quarter earnings expectations on Thursday. Duke Energy North America, the company's troubled in-house merchant energy operation, once again tarnished results. Meanwhile, ExxonMobil turned in another impressive performance. The huge energy company reported a first-quarter profit of $5.44 billion on revenue of $67.6 billion. And although last year's earnings were 23% higher, due to one-time gains, ExxonMobil posted higher operating profits across all of its major business lines. "First-quarter earnings, excluding accounting changes and special items, were a record and improved in all parts of the business," ExxonMobil Chairman Lee Raymond declared. In midday trading, Exxon added 40 cents to $43.52, while Duke sagged 31 cents to $21.51.