The Dow surged to a record Wednesday as U.S. stocks welcomed congressional testimony by Federal Reserve Chair Janet Yellen reiterating the pledge to gradual interest rate increases.
At the closing bell, the blue-chip index stood at 21,534.22, up 0.6 percent.
The broad-based S&P 500 gained 0.7 percent to 2,443.48, while the tech-rich Nasdaq Composite Index jumped 1.1 percent to 6,260.55.
The Dow reached a record intraday high.
An index of airline stocks was up 2.2 percent after the No. 1 U.S. airline, American Airlines Group Inc, reported quarterly results that beat expectations and its shares rose 3.8 percent.
Delta Air Lines Inc, United Continental Holdings Inc , Alaska Air Group Inc, Spirit Airlines Inc and JetBlue Airways Corp shares were up between 1 to 4 percent.
Stocks held their gains after the Fed's latest Beige Book report showed that the U.S. economy grew at a "slight to moderate" pace over the last several weeks across all regions of the country.
Investors will be keeping an eye on second-quarter earnings reports on Friday from big U.S. banks including JPMorgan Chase , Wells Fargo and Citigroup.
Advancing issues outnumbered declining ones on the NYSE on Wednesday by a 3.52-to-1 ratio; on Nasdaq, a 2.23-to-1 ratio favored advancers.