US stocks gave up modest gains Monday to end the session flat as wary investors focused on Greece's struggle to win a debt write-down from private bondholders.
The Dow Jones Industrial Average fell 11.66 points (0.09 percent) to close fractionally lower at 12,708.82, ending a four-session winning streak.
The tech-rich Nasdaq Composite dipped 2.53 points (0.09 percent) to 2,784.17, while the broad-based S&P 500 edged up 0.62 point (0.05 percent) to 1,316.00.
"Continuing talks between the Greek government and the country's bondholders have not made any progress, and the imposition of an embargo on Iranian oil and other sanctions have been approved by the European Union," said Paul Ausick at 24/7WallSt.com.
Financial stocks turned mixed after robust gains. Bank of America was the strongest gainer on the Dow 30-stock index, jumping 2.6 percent. But Citigroup edged up only 0.7 percent and Goldman Sachs fell 0.5 percent.
There were no major economic data releases on the calendar Monday and Tuesday. The Federal Reserve opens a two-day policy meeting Tuesday, followed that night by President Barack Obama's State of the Union address to Congress, expected to focus on the economy.
A shakeup at the top of Research in Motion, the struggling Canadian maker of the BlackBerry, left investors cold.
RIM co-chief executives Mike Lazaridis and Jim Balsillie announced Sunday their resignations after the company steadily lost market share to Apple's iPhone and handsets powered by Google's Android software.
Chief operating officer Thorsten Heins was named president and CEO. RIM shares plunged 8.5 percent on the Nasdaq to $15.56.
Apache added 1.6 percent to $98.38. The oil and natural gas company said it would buy privately held energy assets in Oklahoma and Texas in a $2.85 billion cash-and-stock deal with Cordillera Energy Partners III.
CEO G. Steven Farris said that given weak natural gas prices, oil, not gas, was the driver.
Rival firm Chesapeake Energy soared 6.3 percent to $22.28 after announcing it was cutting back its gas output amid a glut that was eroding prices.
Bonds weakened Monday. The yield on the 10-year Treasury rose to 2.07 percent from 2.03 percent Friday, while the 30-year increased to 3.17 from 3.10 percent.
Bond prices and yields move in opposite directions.