Jim Cramer weighs in on Spirit Airlines, Southwest, Amgen, Biogen Idec, Liberty Oilfield Services, The Chefs Warehouse, Under Armour and more.

Jim Cramer says news on tariffs, FANG stocks, positive research, and the corporate outlook are fueling a stock market surprise.

Stable crude prices could provide a favorable environment for equities that benefit from higher oil prices, such as Occidental Petroleum and EOG Resources.

Goldman Sachs has an attractive view of North American majors and refiners in spite of some headwinds.

The move comes as U.S. gasoline prices skyrocketed Thursday morning due to an East Coast pipeline shutdown by the nation's largest gasoline transporter, Colonial Pipeline Co.

More than 2.2 million barrels per day of U.S. refining capacity was offline due to Hurricane Harvey.

While shut-in crude oil production is good for commodity prices, shut-in refineries will lead to a surplus of product and a lack of demand for electricity won't help.

A change in renewable fuel regulations would be a negative for companies like Chevron and BP, says S&P Capital IQ.

Here are Thursday's top research calls, including upgrades for Advanced Micro Devices, Hess and Juniper, and a downgrade for Fitbit.

Roku's eroding market share, and its need for new investment, will pressure near-term profits, according to KeyBanc analyst Justin Patterson.

“Our investor survey reinforces our views that Elon Musk's recent involvement with Twitter has contributed to negative sentiment momentum in Tesla shares," said Morgan Stanley analyst Adam Jonas.

Mobile carrier companies are always eager to increase revenue through fees customers pay and to outflank their competition with deals.