The Dow pushed to a fresh all-time high Wednesday, but the S&P 500 and Nasdaq retreated from records amid weakness in airline and computer chip shares.
The Dow Jones Industrial Average rose 0.2 percent to close at 26,252.12, eclipsing the record set Monday.
The tech-rich Nasdaq Composite Index dropped 0.6 percent to 7,415.06, while the broad-based S&P 500 lost 0.1 percent at 2,837.54, after both posted multiple record days.
US stocks have rallied in recent weeks as enthusiasm about US tax cuts adds to optimism at improving US and global economic data.
But some observers expect a pullback.
"My sense is that the market is losing some momentum, and it should," said Chris Low of FTN Financial. "This has just been a spectacular run."
"I would be surprised if we don't have a bit of profit taking at some point given how relentless the rally has been," Low added.
General Electric dropped 2.7 percent as it disclosed that the US Securities and Exchange Commission opened an investigation into a hefty charge in its insurance business that contributed to a big loss in the fourth quarter.
Weakness in Apple weighed down the Nasdaq, with the biggest company by market capitalization falling 1.6 percent on negative speculation about iPhone sales in the current quarter.
Airline shares dropped after United Continental said it would boost US seating capacity by four to six percent this year, a move that raised investor worries about overcapacity. United sank 11.4 percent, American Airlines dropped 6.0 percent and Delta Air Lines fell 5.2 percent.
Texas Instruments tumbled 8.5 percent after its forecasts disappointed many analysts who were expecting a more bullish outlook after tax reform. Other chip companies, including Intel and Maxim Integrated Products, also fell.