The claim is strongly supported by multiple sources gathered in this run. The Yahoo Finance X post says U.S. stocks opened higher on April 21, 2026. BlockBeats provides the specific opening figures matching the claim: Dow +0.5%, S&P 500 +0.28%, and Nasdaq +0.27%. The CNBC search-result snippet independently corroborates that the three major indexes began the session with gains and that the Dow was up 0.5%. Although the PANews article shows slightly different percentages, it still supports the core claim that the major U.S. indexes opened higher. Taken together, the evidence supports the statement that U.S. stocks opened higher on April 21, led by a roughly 0.5% gain in the Dow.