The year-over-year reading on consumer prices shows a 4.2% increase. That's the highest since 2008. However, that's compared to April 2020 and its plunging prices at the start of the pandemic. "That annual number is distorted because we were in a pandemic," said Susan Schmidt, head of U.S. equities at Aviva Investors. "People weren't going out. Everything was shutting down. Costs were of course dropping. And so when you look at that in comparison, you're going to get a large number. Markets expected that coming into today, and that's why you're not seeing a huge move in the market this morning." Schmidt says that for the next several months, investors will be focused on whether or not this type of increase is just a blip. "Is this inflation? Or is this just a year-over-year sign that the economy is getting back to normal? And that debate is going to rage on in the coming months. We're not going to know for sure, really, until we get to the fall."

The BBC's Victoria Craig has more.