"The market isn't without issues as it relates to valuations which are full if not somewhat expensive," said Mark Luschini, chief investment strategist at Janney Montgomery Scott in Philadelphia. He expects the Dow to go beyond 22,000, however.
There is also summer seasonality to take into account. Neil Wilson, senior market analyst at ETX Capital in London, said the Dow's run up past 22,000 was "indicative of a bull market speeding to a top."
"August is usually not a great month for stocks, up five times in the last 20, so there is caution about how long this can be sustained beyond earnings season euphoria," Wilson said.
Additional reporting by Saqib Ahmed, Caroline Valetkevitch, Chuck Mikolajczak, Tanya Agrawal, Sweta Singh, Yashaswini Swamynathan and Sinead Carew.
This article was provided by Reuters.