The U.S. stocks ended flat on Monday, with all three major indexes closing within 0.1 percent around the breakeven line, with The Standard & Poor's 500 Index increasing for the fifth day.

With no major U.S. economic data due out Monday, investors focused on the news from Europe. Investors expected that talks between the Greek government and its private creditors will come up with an agreement to avoid a chaotic default.

Meanwhile, Germany successfully sold 12-month bonds with an average yield of 0.07 percent, well below the yield of 0.346 percent at the last auction, suggesting that demand for German bonds has recovered.

Moreover, the European Union on Monday agreed to ban imports of oil from Iran, which worried investors as the embargo may cause a supply shortage and instability in financial markets.

Investors were also keeping a close watch on company earnings, especially from bellwethers such as Apple later in the week.

As for shares, energy shares rose over one percent as oil prices gained on Monday. Financial sectors also rallied thanks to the Greek talk hope. Healthcare sector slightly dropped.

The Dow Jones Industrial Average lost 11.66 points, or 0.09 percent, to 12,708.82. The Standard & Poor's 500 added 0.62 points, or 0.05 percent, to 1,316.00. The Nasdaq Composite Index inched down 2.53 points, or 0.09 percent, to 2,784.17.

On oil market, oil prices gained on Monday after the European Union announced to impose sanctions on Iranian oil, spurring fresh supply concerns.

As of Monday's close, Light, sweet crude for March delivery gained 1.25 dollars, or 1.3 percent to settle at 99.58 dollars a barrel on the New York Mercantile Exchange.

In London, Brent crude for March delivery also rose and last traded above 110 dollars a barrel.

As for dollar, the U.S. dollar fell against major currencies in late New York trading on Monday as investors waited the result of Greek debt talks.

The dollar index retreated back to below 80 as the euro recovered.