That's the highest level for inflation in 30 years, according to The Economist, and well above the United States Federal Reserve's policy goal of two percent inflation over the longer term.

Uncertainty about the nature of inflation has left the U.S. Federal Reserve wedged in an uncomfortable policy position. The Economist explained: 

"As inflation has accelerated economists and officials have debated whether it is a transitory phenomenon—reflecting overstretched supply chains—or a more persistent problem. It is far more than an academic debate. If inflation is short-lived, the right move for the Federal Reserve would be to look through it, aware that jacking up interest rates may do more harm than good. If, however, inflation is stubbornly high, the central bank is duty-bound to tame it,"

Taming inflation could mean tapering bond buying and raising rates more quickly than planned and higher rates tends to slow and, sometimes, stall economic growth.

When making policy decisions, Personal Consumption Expenditures (PCE) is the Fed's preferred inflation gauge. The readings for the CPI and the PCE rely on information from different sources.

"The CPI uses data from household surveys; the PCE uses data from the gross domestic product report and from suppliers. In addition, the PCE measures goods and services bought by all U.S. households and nonprofits. The CPI only accounts for all urban households," reported Fanglue Zhou of Callan Associates.

PCE data will be released on November 24.

Major U.S. stock indices retreated a bit last week, according to Ben Levisohn of Barron's, leaving the Standard & Poor's 500 Index up 24.7 percent year-to-date. The yield on 10-year U.S. Treasuries rose last week.