Another drive lower in crude oil prices pressured the energy sector. West Texas Intermediate crude oil fell 1.6% to $34.95 a barrel after recent data on U.S. inventories stoked fears over a supply glut. Crude closed at its lowest level since February 2009. 

Major oilers including Chevron (CVX ) , Kinder Morgan (KMI) , PetroChina (PTR) , Royal Dutch Shell (RDS.A)  and BP (BP) fell, while the Energy Select Sector SPDR ETF (XLE) slid 1.7%. 

Markets rallied on Wednesday after months of uncertainty over rate hikes came to an end when the Federal Reserve pulled the trigger. The S&P 500 was up 1.5%, the Dow Jones Industrial Average added 1.3%, and the Nasdaq rose 1.5%.

"We got a pop on the reduction of uncertainty," Brad McMillan, chief investment officer for Commonwealth Financial Network, told TheStreet. "The Fed actually succeeded remarkably well in communicating what they were going to do."

The hike was a pre-emptive measure to give the central bank room to move in case of a downturn, Fed Chair Janet Yellen said in a press conference after the announcement.

"It's not about the markets, it's about command and control," said Alan Morley, regulatory compliance and surveillance practice lead at GFT USA. "This announcement indicates a stabilization of post-2008 policies. In fact, if they hadn't announced a rate hike, there would have been cause for concern as it would have indicated that the markets haven't recovered as anticipated."

A number of major banks increased their prime rates on Wednesday afternoon, including Wells Fargo (WFC - Get Report) , USB (USB - Get Report) and Bank of America (BAC - Get Report) .

The number of new claims for unemployment benefits in the U.S. fell 11,000 to 271,000 in the past week. Analysts had expected weekly jobless claims to fall slightly further to 270,000.

Business activity in the Philadelphia region contracted in December, according to the latest numbers released Thursday. The Philadelphia Fed index fell to negative 5.9 over the month.

Apple (AAPL - Get Report)  named Jeff Williams as its new chief operating officer. Williams has been with the company for 17 years and has overseen its supply chain since 2010. The tech giant also announced Johny Srouji as its new senior vice president for hardware technologies.

Pharmaceutical entrepreneur and CEO of Turing Pharmaceuticals, Martin Shkreli, was arrested Thursday morning by federal authorities on charges of securities fraud. Shkreli rose to infamy earlier this year after raising the price of a recently acquired drug to $750 a pill from $13.50 overnight. The charges are unrelated to the price-gouging scandal.

General Mills (GIS - Get Report) fell nearly 1% after a disappointing second quarter and downbeat outlook. The company earned 82 cents a share in its recent quarter, missing estimates by a penny, while sales fell 6.1%. The owner of Betty Crocker and Cheerios expects full-year sales to decline at a low single-digit percentage rate. The company had previously forecast flat sales for the year.

Avon Products (AVP) soared more than 25% after receiving a $605 million investment from Cerberus Capital Management. Reports have been swirling that the private-equity firm is nearing a deal to buy 80% of Avon Products' (AVP) North American business and take a nearly 17% stake in the cosmetics company.

U.K. drugmaker AstraZeneca (AZN) agreed to buy a 55% stake in Dutch drug company Acerta Pharma for $4 billion. AstraZeneca will pay $2.5 billion upfront, and another $1.5 billion when Acerta gets the first regulatory approval for blood cancer drug acalabrutinib for any indication in the U.S., or the end of 2018, depending on which comes first.

Oracle (ORCL) climbed more than 2% despite reporting a mixed second quarter. The enterprise software developer earned 63 cents a share, 3 cents above expectations. Revenue slid 6.3% to $9 billion, missing estimates by $60 million.

Pier 1 Imports (PIR) tumbled 14% after issuing a disappointing outlook. The homewares retailer expects to earn 18 cents to 22 cents a share in its fourth quarter, well below analysts' estimates of 36 cents a share.

FedEx (FDX) jumped 5% on a better-than-expected second quarter. The package delivery service earned $2.58 a share, 8 cents above estimates. Revenue climbed 5% to $12.5 billion, edging past forecasts of $12.42 billion.