U.S. stock indexes slid more than 1 percent on Thursday, led by losses in bank stocks, as Russia’s all-out invasion of Ukraine sparked a widespread selloff in global markets. On the benchmark S&P 500, all the 11 major sectors slipped into the red, with financial stocks falling 2.9 percent, while tech and consumer discretionary stocks lost more than 1 percent each. Russian forces invaded Ukraine in a massed assault by land, sea, and air, the biggest attack by one state against another in Europe since World War Two. The escalation in conflict rattled financial markets as global shares slumped and oil prices broke above $100 a barrel, while safe havens gold, government bonds, and the dollar surged in the flight to safety. The United States and its allies promised tough sanctions against Moscow after weeks of fruitless diplomatic efforts and an initial wave of modest sanctions. Most big lenders, including …