NEW YORK (TheStreet) -- Stocks solidified earlier gains on Thursday as consumer prices remained weak, potentially giving the Federal Reserve pause in its rate hike plans. 

The S&P 500 was up 0.75%, the Dow Jones Industrial Average added 0.88%, and the Nasdaq gained 1.1%.

Fitbit (FIT) surged in its market debut on the New York Stock Exchange on Thursday. The wearable tech company rocketed 50.7% higher to $30.16, well above its initial pricing of $20 a share for its float of 36.6 million  shares.

Conditions in the Philadelphia Fed district markedly improved. The Philadelphia Fed business outlook survey climbed to 15.2 in June from 6.7 in May, far higher than an expected reading of 8. 

Consumer prices in the U.S. continued to show weakness, potentially giving pause to the Fed's plans for interest rate hikes. Prices in May rose 0.4%, attributable to a 10.4% bounce in gasoline prices. The reading came in below estimates for an increase of 0.5%. Core CPI rose 0.1%, below economists' forecasts of a 0.2% increase excluding volatile items such as food and energy.

"Underlying price pressures should remain relatively contained, which will provide the Fed with the necessary justification to be very "gradual" in the pace of policy tightening," said TD Securities' Millan Mulraine.

Weekly jobless claims fell to 267,000 in the week ended June 12, after a 279,000 reading a week earlier. Economists expected the number of people filing unemployment benefits claims to fall to 276,000.

Markets were also boosted by the Fed's decision on Wednesday to leave interest rates unchanged at near-zero crises levels for another month. However, the Fed signaled it is prepared to move later this year, according to a press release. Click here for more.

"They do want to demonstrate to the markets that they are ready, willing and able to raise rates," said David Schiegoleit, managing director for investments at U.S. Bank's Private Client Reserve, in a call. "The Federal Reserve is loathed to get behind the curve when it comes to inflation"

European stocks fell again as Greece's unresolved debt problems weighed on markets. Greece's central bank has admitted that the country will default and exit the eurozone if a deal with its creditors cannot be formed, becoming the first developed country to default on the International Monetary Fund.

Eurozone finance ministers are pushing Greece to introduce a round of austerity measures in exchange for further debt relief in a Eurogroup meeting Thursday. Greece has until the end of the month to repay its debts to the IMF. Click here for more.

Oracle (ORCL) shares fell 8.1% after a disappointing fourth quarter. The tech company earned 78 cents a share, 9 cents below estimates, while revenue of $10.71 billion fell 5.5% from a year earlier. Sales were hit by a 17% decline in license revenue.

Kroger (KR) jumped nearly 2% after the grocery store operator said it expects same-store supermarket sales growth of 3.5% to 4.5% over the full year ending in January.

Apple (AAPL) shares were on watch after Apple Watch sales estimates were released. Sales reportedly came in at around 2.79 million from launch through to mid-June, according to Reuters.

Rite Aid (RAD) fell 3.5% despite reporting a better-than-expected quarter with same-store sales up 2.9%. Pharmacy sales increased 3.6%.

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