Wall Street was mixed on Monday, with major benchmark indexes moving in different directions as market participants tried to balance all the factors affecting investor sentiment. It's unclear whether attempts to negotiate a settlement to the trade war between the U.S. and China will result in tariffs getting lifted, and economic slowdowns globally haven't yet succeeded in eliminating domestic growth. Some companies reported encouraging news that sent their share prices higher. PG&E (PCG -0.78%), Southwestern Energy (SWN -1.13%), and Navistar International (NAV) were among the day's top performers. Here's why their stocks did so well.

PG&E could get a buyer

Shares of PG&E rose by 10% after the bankrupt utility received an offer to purchase some of its assets. The city of San Francisco has offered to pay $2.5 billion to acquire the company's power lines and electrical infrastructure serving the Bay Area metropolis, including some assets outside the city limits. PG&E said that it would continue to work to ensure that citizens of San Francisco and the surrounding areas get the power they need, but it's unclear whether the utility will work the city's offer into its proposed bankruptcy reorganization plan. Shareholders are getting impatient, but there's still hope that the company will emerge from bankruptcy without its investors losing everything.

Rows of power transmission lines and transformers near sunset or sunrise.

Image source: Getty Images.

Southwestern gasses up

Southwestern Energy's stock climbed 16% on a good day in the natural gas market. Futures contracts for October delivery of natural gas climbed almost 4% on Monday, as investors reacted to more-favorable weather forecasts and speculators closed out their bets against the price of the fuel. Unlike many fossil fuel companies  that have shifted their attentions toward oil, Southwestern Energy remains one of the lowest-cost providers of natural gas in the market. With prices stuck at low levels, that's been a tough strategy to follow, but Southwestern shareholders seem more hopeful today that it could end up being a winning move in the long run.

Navistar keeps driving higher

Finally, shares of Navistar International rose another 10%, adding to their gains from last week. The truck maker's recent climb began after Navistar reported its fiscal third-quarter financial results on Wednesday, which included sales gains of 15% and strong performance in its heavy truck and bus businesses. The company has been a victim of concerns about slowing economic growth across the globe, but it believes that it can build market share and take away business from its competitors even in a sluggish industry environment. If that's the case, then it could see further gains from here.