Image source: Transocean.

The stock market has been prone to quick changes in sentiment lately, and Monday showed how fast investors have been flooding back into the market even after somewhat troubling news. After falling last Friday in the wake of a sluggish employment report, stocks bounced back after Federal Reserve Chair Janet Yellen tried to thread the needle in a speech to policymakers in Philadelphia. The central banker noted that the jobs report was disappointing but didn't specifically suggest its implications for the Fed's rate-setting meeting later this month. Investors chose to take the positive view, sending the Dow up by triple digits and other major market benchmarks rising by around two-thirds of a percent. Some stocks did even better, and Transocean (NYSE:RIG), Exelixis (NASDAQ:EXEL), and CF Industries (NYSE:CF) were among the best performers on Monday.

Transocean jumped 15% on a strong day for the energy sector. Oil prices climbed close to the $50-per-barrel mark, and the prospect of higher prices for crude oil and natural gas raised the possibility that Transocean and other offshore drillers could finally start to see a more prolonged turnaround in their fortunes. Even at these higher prices, many oil and gas exploration and production companies will be loath to hire Transocean or its rivals to move forward with expensive offshore drilling projects. Of even more concern is the fact that rates on projects are low enough that it will be hard for Transocean to earn a profit even when it does manage to win business. Nevertheless, given how far energy stocks have plunged, even the slightest bit of good news has been enough to send stocks like Transocean up sharply in anticipation of a longer-term bounce.

Exelixis climbed 11% in the wake of positive phase 3 trial results for its renal cell carcinoma treatment. Cabometyx was found to have provided benefits in progression-free survival and overall survival of this form of kidney cancer, according to data that the company and its partner Ipsen released in a presentation before the American Society of Clinical Oncology's annual meeting. As CEO Michael Morrissey noted, "We are dedicated to exploring the full potential of Cabometyx to help as many patients as possible." The findings were independent of the presence of bone metastases as well as other factors, which could potentially broaden the scope of use for the treatment if it wins approval from the Food and Drug Administration.

Finally, CF Industries finished up 8%. The fertilizer company received an upgrade from analysts at Credit Agricole, which has moved its opinion of the stock up from sell as recently as last December to a full buy now. The move comes shortly after some of Credit Agricole's analyst peers had downgraded the stock late last month, and many investors aren't certain how the fertilizer company plans to proceed following the termination of its deal to acquire OCI. Now that tax-inversion benefits are no longer available, CF Industries will have to focus on the fundamentals of its business, and farm commodity prices haven't jumped to the same extent as some other commodities outside the agricultural sector. CF has room to rebound further, but it's unclear whether now will be the beginning of a longer run or just be a brief pause in its downward track.

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