U.S. stock indexes opened higher on Thursday, powered by banks and megacap growth stocks that led a rally in the previous session after Federal Reserve Chair Jerome Powell pointed to a cautious tightening amid the Ukraine crisis. The Dow Jones Industrial Average rose 81.52 points, or 0.24 percent, at the open to 33,972.87. The S&P 500 opened higher by 14.77 points, or 0.34 percent, at 4,401.31, while the Nasdaq Composite gained 85.57 points, or 0.62 percent, to 13,837.59 at the opening bell.