Wednesday was a mixed day on Wall Street, and major indexes spent time on either side of the unchanged mark during the trading session. Early gains evaporated after the federal government appeared to reverse course on its traditional strong-dollar policy, as Treasury Secretary Steven Mnuchin reacted to dollar weakness unconventionally by focusing on its positives for U.S. exporters. Yet even with the downward pressure on the overall market, some stocks still managed to post sizable gains. General Dynamics (GD -0.29%), McDermott International (MDR), and Petroleo Brasileiro (PBR 0.26%) were among the best performers on the day. Below, we'll look more closely at these stocks to tell you why they did so well.

General Dynamics flies higher

Shares of General Dynamics picked up 6% after the company reported favorable fourth-quarter and full-year financial results. The industrial giant reported solid sales gains for several key business segments, including an 8% rise in combat systems and a 4% advance for the aerospace group. Order activity for Gulfstream business jets soared during the period, with some analysts arguing that tax reform made purchases more attractive, while others noted that some buyers might have wanted to rush to lock in tax benefits against high-rate income in 2017 before corporate tax rates fell for 2018. With strong backlogs and good conditions in its key markets, General Dynamics appears poised to keep gaining altitude.

Gulfstream production facility with several business jets parked outside on a clear sunny day.

Image source: General Dynamics.

McDermott gives good guidance

McDermott International stock climbed 14% in the wake of several positive news items. Foremost was revised guidance for the year just ended as well as for 2018, which included calls for $0.60 to $0.63 per share in earnings on $3 billion in revenue for 2017, and profit of $0.42 to $0.52 per share in 2018 on revenue of $3.1 billion to $3.3 billion. The oil services company also announced a new offshore platform structure construction contract with major energy player Saudi Aramco, carrying a value of between $50 million and $250 million. As oil prices rise, greater activity levels in the energy industry could point to even more success for McDermott in the future.

Could Petrobras keep its CEO?

Finally, shares of Petroleo Brasileiro rose nearly 9%. The Brazilian oil giant got good news from CEO Pedro Parente, who said that he might stay with the company even beyond the next Brazilian election. Petrobras has been stuck in the middle of government scandals that have risen to the highest levels of government, including a corruption conviction against former Brazilian President Luiz Inacio Lula da Silva. Yet Parente's statement bodes well for the state-controlled Petrobras, raising hopes among investors that the energy company might gain more independence and be in a better position to reward shareholders.