Americans won’t feel isolated from protests in the Middle East much longer. With protests roiling key oil-producing nations—especially Libya—oil prices shot up Tuesday, causing a nosedive in stocks. Overall, the Dow Jones Industrial Average sank 1.4 percent, the biggest drop since November 2010. But the biggest losers weren’t oil-related: Walmart and Bank of America both had rotten days after reporting bad news on sales and credit-card revenues, respectively. The price of a barrel of oil saw its biggest one-day gain in more than two years. Meanwhile, the S&P tumbled 3.1 percent.