U.S. stocks were mostly lower on Wednesday, as a slide in oil prices weighed on energy shares and as investors eyed negotiations between Greece and its international creditors.

The Dow Jones Industrial Average slipped 76 points, or 0.4%, to 17792.

The S&P 500 fell four points, or 0.2%, to 2064. Energy stocks fell 1.4%, notching the index’s second-biggest sector declines, as oil prices fell 2.6% to $48.73 a barrel.

The Nasdaq Composite added six points, or 0.1%, to 4794, buoyed by Apple Inc. whose shares rose 1.3%. On Tuesday, Apple became the first $700 billion company in the U.S.

European stocks fell on concerns about Greece, with the Stoxx Europe 600 index down 0.4%. The new government in Athens wants to ease conditions on its bailout program, but has encountered resistance from its creditors. The current bailout is due to expire at the end of the month. Eurozone finance ministers will meet Wednesday in an emergency session to discuss Greece. The latest standoff pushes Greece closer to a default and has revived fears of the prospect of a forced exit by the country from Europe’s single-currency union.

The constant political interplay in Europe winds up playing considerable tug of war on sentiment, said Jack Caffrey, equity portfolio manager at J.P. Morgan Private Bank. Markets prefer greater certainty, he added.

U.S. stocks have seesawed this year, with the Dow up just 0.3% in 2015 and 1% below its record of 18053.71, through Tuesday’s close. The S&P 500 is up 0.5% for the year and remains 1.1% below its closing high of 2090.57, also through Tuesday. Headlines about Greece’s debt negotiations have led to swings in U.S. stocks lately, even though many investors believe a deal will be reached. The prospect of an eventual interest-rate increase in the U.S. is also adding to swings.

We’ve seen this market. whip around with increasing volatility, said Sahak Manuelian, a managing director at Wedbush Securities. He said he has noticed investors selling some of the stocks that have performed well over the last year and buying some beaten-up sectors, like energy.

For the month, utilities stocks on the S&P 500 have fallen 4.3% while health-care stocks have gained just 1.5%, marking the smallest advance among S&P sectors. Both sectors posted strong gains in 2014.

Diane Jaffee, who oversees about $8 billion in relative value strategies as a senior portfolio manager at TCW Group Inc. said she’s bought some exploration and production companies in the energy sector this year, after holding no such companies in 2014.

Some of the worries about the decline in the price of oil being reflective of a huge global economic decline seem to be overdone, she said.

In other markets, gold futures lost 0.7% to $1223.40 a barrel.

Treasury prices were little changed, with the yield on the 10-year note at 1.994% versus 1.991% on Tuesday. Yields rise as prices fall.

The economic calendar is light this week. Tuesday’s report on job openings, which were at a 14-year high in December, supports the idea that slack is lessening in the job market, said Mr. Caffrey. Nothing makes consumers more confident than thinking they’re participants in a robust jobs market, he said.

Among individual companies, Akamai Technologies Inc. said its fourth-quarter earnings rose 21% on broad revenue growth. Shares rose 2.4%.

Time Warner Inc. said revenue slipped 1% in its December quarter. The company raised its quarterly dividend by 10% to 35 cents. Shares rose 0.5%.

PepsiCo Inc. said its profit and revenue fell in its fourth quarter as foreign-currency effects weighed. The company said it plans to spend $8.5 billion to $9 billion on stock buybacks and dividends in 2015. Shares added 2.2%.

Write to Saumya Vaishampayan at saumya.vaishampayan@wsj.com

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