Inflation reading Tuesday expected to show prices at nearly a three-year high

An inflation reading due Tuesday is expected to show price gains at their highest level in nearly three years, setting up potential challenges for investors and Federal Reserve officials alike. April's consumer price index , a broad gauge of goods and services costs across the U.S. economy, is forecast to reach an annual rate of 3.8%, owing to a 0.6% jump in monthly prices as the oil shock continues to slam consumers, according to the Dow Jones consensus among economists. …