Shortly after the open, a regional manufacturing report also showed weakness.
Soft consumer spending data in the U.S. offset positive sentiment from gains in overseas bourses despite another tightening move by China's central bank.
The Dow Jones Industrial Average dropped 13 points to 13,108, as 20 of its 30 components dropped.
The S&P 500 index fell 0.5 points to 1,493, while the Nasdaq Composite rose 7.2 points to 2,550.
Even Dow component Verizon Communications , whose earnings and revenue topped Wall Street expectations only rose fractionally.
And brokerage behemoth Merrill Lynch only gained 0.2% after saying it planned to buy back up to $6 billion of its own stock under a new share repurchase program. The latest move follows a $5 billion buyback program completed in October 2006 and a $6 billion program completed in February 2006.
Stocks rode a four-session winning streak to close Friday at another record high. The Dow has gained ground in 11 of the last 12 sessions, and in 18 of the last 20. .
Philip Roth, chief technical market analyst at Miller Tabak said there have been several trend "non-confirmations" that suggest the stock market may need to consolidate, but said they were "not insurmountable negatives."
"In the meantime, as long as initial support holds and pullbacks do not generate accelerating downside momentum, probabilities favor attempts to extend the advance," Roth said in a research note.
On the data front, the core personal consumption index rose 2.1% in the past 12 months, the Commerce Department said, still above the 2% ceiling of the Federal Reserve's comfort zone, but down from a 2.4% rise in February.
U.S. consumer spending grew a little less than expected, while personal incomes rose a bit more than forecast.
The U.S. dollar was mixed following the data, with the greenback relatively flat vs. the Japanese yen at 119.56 but up 0.2% against the euro at $1.3621.
The tame inflation data helped boost Treasurys, sending yields lower. The yield on the benchmark 10-year note fell 0.028 percentage points to 4.670%.
The commodities markets were relatively steady, with crude for June delivery up 6 cents at $66.52 a barrel in electronic trading, and June gold up $1.30 at $683.10 an ounce.
In overseas markets, bourses in Asia were mostly higher, with China's Shanghai Composite rising to a record, after China's central bank said over the weekend that it will lift the reserve requirement ratio for bank loans by 0.5 percentage points, in effect a tightening of monetary policy.
In Europe, U.K., German and French markets all advanced. See and .
Also of note, Delta Air Lines , the No. 3 U.S. air carrier, emerged from bankruptcy on Monday a year ahead of schedule after a 19-month restructuring.
On the deal front, International Securities Exchange is in talks to be acquired by Deutsche Boerse for $2.8 billion, and Dominion Resources agreed to sell its Gulf of Mexico fields to Eni for $4.76 billion.
By Tomi Kilgore