NEW YORK (TheStreet) -- Stocks retreated from a record run during Thursday's session as continuing Greek debt talks triggered investor nerves.

The S&P 500 was down 0.18%, and the Dow Jones Industrial Average fell 0.17%. The Nasdaq slipped from its record close on Thursday, down 0.21%.

"There is a sense of unease in the markets as the clock continues to tick down to the approaching deadline for Greece to strike a deal to avoid a debt default," said TD Securities' Millan Mulraine. 

The European Central Bank reportedly raised its funding cap on Emergency Liquidity Assistance for Greece's banks, according to Reuters. The move follows on from failed debt talks at a Eurogroup meeting on Thursday.

European Council President Donald Tusk has called an emergency summit for further debt talks on Monday. Eurozone finance ministers from 19 countries will convene to try to overcome the stalemate. Eurozone finance ministers want Greece to introduce a round of austerity measures in exchange for further debt relief. Greece has until the end of the month to repay its debts to the International Monetary Fund. Click here for more.

Trading could be more volatile than usual on Thursday given it is a quadruple-witching session, one of four days of the year in which futures and options contracts expire at once. There is no economic data due out Friday.

Hershey (HSY) - Get Report slid 2.4% after the chocolate company reduced its 2015 forecast on weakened growth in China. The company expects full-year earnings of $4.10 to $4.18 a share, below estimates of $4.31 a share.

KB Home (KBH) - Get Report added nearly 5% after second-quarter profit and sales beat estimates. The homebuilder earned 10 cents a share, 2 cents higher than expected, while revenue of $622.97 million jumped 10.3% from a year earlier.

Fitbit (FIT) - Get Report shares extended Thursday's gains, climbing 1.2%. The wearable tech company surged in its market debut on the New York Stock Exchange on Thursday, rocketing 48% higher to $29.68, well above its initial pricing of $20 a share for its float of 36.6 million shares.

ConAgra Foods (CAG) - Get Report added 5.6% on news Jana Partners had taken a 7.2% in the company. The activist investor argued the company's shares are undervalued and is seeking a change in its board.

Sequential Brands (SQBG) - Get Report and Martha Stewart Living Omnimedia (MSO) were on watch after a late-day surge a day earlier. The two gained on a Wall Street Journal report that Sequential Brands was nearing an agreement to purchase Martha Stewart for an undisclosed amount. Martha Stewart jumped 26.3%.

CarMax (KMX) - Get Report slid nearly 5% after reporting in-line quarterly earnings and a revenue miss. The car dealership reported a 4.9% increase in used unit sales at comparable stores.